PromptPalette User Guide

What is PromptPalette?

PromptPalette is a Chrome extension for people who create images in ChatGPT or Gemini by giving the same instructions again and again: “turn this screenshot into a watercolor”, “make line art from this image”, “create a blog thumbnail based on this”.

Doing that by hand means pasting the image, opening the tools menu, choosing image creation, and pasting the prompt, every time. PromptPalette does all of that from a single shortcut or a click on its toolbar icon.

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When is it useful?

PromptPalette is most useful when the image changes but the instructions stay the same. For example:

• Screenshots into illustrations. You capture part of a web page, slide or app and always ask for the same art style.
• Making materials. You turn photos or diagrams into line art, icons or coloring pages for documents and lessons.
• Thumbnails and social posts. You create a thumbnail in a fixed format and aspect ratio from a screenshot of each article or video.
• Comparing services. You send the same image and prompt to both ChatGPT and Gemini and compare the results.
• Long, carefully tuned prompts. You have multi-line prompts that you don’t want to retype or hunt down in a notes file.

Requirements

• Google Chrome 120 or later. This guide uses Windows key names; PromptPalette was developed and tested on Windows 11.
• You are signed in to ChatGPT and/or Gemini in Chrome, with an account that can create images. Image generation limits and plans are set by each service.
• No API key, extra software or account for PromptPalette is needed.

Install

1. Open the PromptPalette page in the Chrome Web Store and click Add to Chrome.
   Open in Chrome Web Store
2. Click the puzzle-piece Extensions icon in the Chrome toolbar and pin PromptPalette so its icon is always visible.
3. Reload any ChatGPT or Gemini tabs that were already open.

First-time setup

1. Open Settings. Right-click the PromptPalette icon and choose Options. You can also click Settings in the panel that appears during a run.
2. Choose the display language. Language / 表示言語 offers Auto, English and 日本語. Auto follows Chrome’s language.

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3. Write your first prompt. The first preset is named “Default” and is empty. Give it a name and type the prompt you always use. Line breaks and blank lines are kept exactly.

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4. Click Save all settings at the bottom of the form. Nothing is applied until you save.
5. Check the shortcut. Click Open keyboard shortcut settings (or go to chrome://extensions/shortcuts) and confirm that Run with a clipboard image has Ctrl+Shift+Y. If another extension already uses it, Chrome leaves it blank, so assign any free key.

Use it in ChatGPT

This is the default flow, with auto-send off. You review everything before sending.

1. Copy an image. Press Win+Shift+S and select an area, or copy an image from anywhere. Exactly one PNG, JPEG or WebP image up to 20 MiB is supported.
2. Open an empty ChatGPT chat. The message box must be empty, with no attachments, and ChatGPT must not be generating a reply.
3. Press Ctrl+Shift+Y or click the PromptPalette icon. A panel appears at the top right with your presets, the prompt that will be used and a preview of the image.

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4. Click Prepare. PromptPalette works through six steps (1/6–6/6): it checks the page, gets the image, attaches it, waits for the upload, selects Create image and enters the prompt. Don’t type in the message box while it runs.

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5. Review and send. When the panel says Ready, the image, the Create image mode and your prompt are in place. Change anything you like, then send it yourself.

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Use it in Gemini

Gemini works the same way. The panel also shows an aspect ratio selector, filled in from the preset. Changing it in the panel affects only this run.

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• Available ratios: Unspecified, 1:1, 9:16, 3:4, 4:3, 16:9.
• Unspecified leaves Gemini’s ratio control untouched. If a ratio is still selected from earlier, it stays.
• The ratio applies to Gemini only. ChatGPT ignores it.

Auto-send: from screenshot to result in one step

If you always use the same preset, turn on auto-send. PromptPalette then skips the panel, uses the default preset, and sends the request once all checks pass.

1. In Settings, under Device settings, check ChatGPT: send automatically after preparation and/or Gemini: send automatically after preparation, then click Save all settings.

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2. Copy an image, open the chat and press the shortcut. The image is attached, image mode is selected, the prompt is entered and the request is sent.

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Use an image file instead of the clipboard

To start from a file on your PC, either

• assign a key to Choose an image file and run at chrome://extensions/shortcuts (unassigned by default), or
• set Input source for the toolbar icon to Image file picker in Settings, so that clicking the icon opens a file picker.

Choose one PNG, JPEG or WebP file up to 20 MiB. If Chrome doesn’t open the picker right away, click Choose image file in the panel. Canceling the picker ends the run without changing the chat. The file name doesn’t matter, and the file and its path are never stored.

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Share presets across your PCs

You can share presets between PCs that use Chrome with the same Google account. Sharing is off by default and is controlled in Sharing with other PCs in Settings.

• Shared: presets (names, prompts, ratios) and the default preset only.
• Not shared: Device settings (input source, auto-send, Ctrl+V), display language, images, diagnostics and this PC's backups. It does not sync your whole PC or Chrome settings.
• The Share presets with my other PCs switch is saved on this PC as soon as you click it (no need for Save all settings). Turning it on does not send anything.
• Save all settings saves presets and Device settings. While sharing, preset changes are also sent to your other PCs.

What the status means

The page also shows Last imported, Last sent from this PC and Last checked. Last sent is when this PC wrote to Chrome sync storage; it does not confirm that other PCs received it. PromptPalette never shows a "sync complete" message that would promise delivery to every PC.

Start sharing on your first PC

1. On the PC that has your presets, open Settings, check the presets and click Save all settings.
2. Turn on Share presets with my other PCs. The status shows "Waiting for presets from your other PCs."
3. Click Start sharing with this PC's presets and confirm. You cannot start if no preset has a prompt. If shared data from another PC has already arrived, it does not start and asks you to review that data instead.
4. When the status shows "Sharing presets with your other PCs.", this PC is ready.

Add another PC

1. Install PromptPalette on the new PC and turn on Share presets with my other PCs in Settings. This PC does not send anything.
2. Wait for presets from your other PCs. How long it takes depends on Chrome sync. Check for updates shows whether they have arrived.
3. If this PC still has only the initial empty preset, the received presets are imported and the PC joins sharing.
4. If you already entered presets on this PC, nothing is replaced automatically. Choose Use the received presets (this PC's presets are kept in backups) or Keep both (adds this PC's presets to the received ones and shares the result).

You can edit and save presets while waiting. They stay on this PC and are not erased by presets that arrive later.

If presets do not arrive

• Is every PC signed in to Chrome with the same Google account, with Extensions turned on in Chrome sync?
• Is PromptPalette 3.0.0 or later on every PC? (Check at chrome://extensions.)
• Has one PC started sharing? If none has, nothing will arrive.
• Check for updates does not force a download from Google. It only checks what has reached this PC. "No new updates have reached this PC" can appear even if a recent change from another PC is still on its way. Check again later.
• If you are in a hurry, move presets with Export settings / Import settings file.

Everyday editing, saving and receiving

• Edit presets on any PC and click Save all settings; PromptPalette writes them to Chrome sync storage for your other PCs. A successful write is not the same as arrival on other PCs.
• Saving only Device settings, or saving unchanged presets, sends nothing.
• Changes from other PCs are checked at Chrome startup, when you open Settings, before a run and when Chrome receives an update. Safe updates are imported automatically, and the previous presets are kept in backups.
• If an update arrives while you are editing in Settings, your screen is not changed. When you save, you are asked first; if you continue, the received presets are kept in backups.
• Turning sharing off keeps this PC's presets and does not delete shared presets on other PCs.

Updates that need review (simultaneous edits, offline edits, many deletions)

In these cases, nothing is applied automatically; both the current and the received presets are kept and you are asked to choose. Auto-send does not run while such an update is waiting.

• If you intentionally removed many presets or emptied prompts, click Apply this update on each other PC. The PC where you save also asks before saving.
• Keep both copies presets whose content differs and marks them "(other PC)". It is not available if the total would exceed 20 presets.
• The version you did not choose is kept in this PC's backups.
• An older update arriving late never rolls back newer presets. Partially received or unreadable data is never used.

Send unsent changes

If sending fails (capacity exceeded or Chrome could not write), the change is saved on this PC and the status shows "Changes on this PC have not been sent to your other PCs yet." Wait a while and click Send unsent changes. Before sending, PromptPalette checks for updates from other PCs; if one has arrived, it does not overwrite it and shows it as an update that needs review.

Restore from a backup (this PC only)

1. Open Advanced (restore, replace, clean up).
2. In Version to restore, choose by date, reason and number of presets. Up to 20 earlier versions are kept before overwrites and received updates, with up to 6 more reserved for important moments (before starting, joining or replacing). Identical versions are kept only once.
3. Click Restore the selected version on this PC. Only this PC changes. While sharing, it becomes an unsent change and is not sent to other PCs until you click Send unsent changes.

Replace shared presets with this PC's presets

Advanced → Replace shared presets with this PC's presets replaces the shared presets on your other PCs with this PC's full set. Before it runs, it shows the number of presets on this PC and in the current shared set, how many presets will disappear, and how many waiting updates will be kept in backups instead of imported. Other PCs ask before applying if many presets are removed, and each PC keeps the previous presets in its backups. You do not need this for normal editing.

Updating from 2.1.0 or earlier

Version 3.0.0 replaces the old sync method, in which every PC overwrote the same storage, with one where each PC writes its own area and the receiving PC checks updates before applying them. Shared presets do not move automatically between PCs on old versions and PCs on 3.0.0. Update in this order:

1. Before updating, click Export settings on each PC and keep the JSON file.
2. Update PromptPalette to 3.0.0 on every PC (the Chrome Web Store version updates automatically; check the version at chrome://extensions). Updating does not reset presets and does not send anything by itself.
3. Do not edit presets on PCs still running the old version until every PC is updated. Edits made there appear on 3.0.0 PCs as "An update arrived from a PC using an old version of PromptPalette" and can be applied after review.
4. After updating, edit presets on one PC and click Save all settings; the change reaches your other PCs with the new method. PCs that were sharing in 2.1.0 are treated as already joined.
5. Once every PC is updated, you can optionally free space with Advanced → Clean up old sync data, which deletes the sync data used by old versions.

The "previous presets" kept by 2.1.0 are carried over to the 3.0.0 backups as "previous backup from old version" (protected). Presets lost under earlier versions may be found there, but recovery cannot be guaranteed.

Settings reference

Presets

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Device settings

These apply only to the current PC and are never synced.

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Sharing with other PCs

For the switch, status and actions, see Share presets across your PCs.

Backup and migration

• Export settings saves promptpalette-settings.json, which includes your prompts. Keep it somewhere safe, and always export before removing or reinstalling the extension.
• Import settings file loads a file into the editor only. Click Save all settings to apply. Auto-send is turned off after an import for safety. While sharing, saving also sends the presets to your other PCs (you are asked first).
• Files exported by earlier versions (format version 2) can be imported. Files in a newer format are not imported; you are asked to update instead.

Keyboard shortcuts

Change them at chrome://extensions/shortcuts. Shortcuts work only while Chrome is the active window.

Diagnostics

Shows the latest run message. Show diagnostics displays the details, and Copy diagnostics copies them to the clipboard. They include only the version, site, stop stage, error code, number of upload-field candidates, time, and sync state and history. Images, prompts, preset names and chat URLs are never included. Copying replaces your clipboard contents, including any copied image, so you are asked first.

Version and license

The top of the settings page, under the title, shows the version and links to the MIT License and the Source code (GitHub) (3.0.1 and later).

Progress and safety

PromptPalette is designed never to overwrite or lose anything you typed.

• Checks before starting. It stops without changing the chat if the message box already has text or attachments, another tool is selected, or a reply is being generated.
• Stops on unexpected changes. If you edit the message box, switch chats, or the site layout changes during a run, it stops and leaves what is there.
• No automatic retries. Attachments and sending are never repeated automatically.
• Attaching is tried only once: if a run fails after an attachment was attempted, PromptPalette does not attach again by another method.
• Runs that stopped before doing anything can be repeated right away: for example, when the upload field could not be identified, the panel says "No image was attached, no text was entered and nothing was sent." and no lock is set.
• Details: after an error, this panel button shows the error code, stop stage, version and whether attaching or sending happened. Use it to check what caused the error.
• Panel buttons: Settings opens Settings, Cancel stops the remaining steps (it cannot undo an upload or a send that already happened), and Close hides the panel.
• “I checked the remaining draft — unlock”. After a run stops, or after you prepare without sending, the chat stays locked so that nothing is attached twice. Check and clear the message box yourself, then click this button. After a successful “prepare without sending”, you can also simply run again once the box is empty.

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Troubleshooting

Privacy and permissions

• Images are handled only in the open ChatGPT or Gemini tab during a run and are never stored.
• PromptPalette has no server of its own. Your image and prompt go only to the ChatGPT or Gemini chat you are using, under that service’s terms.
• Settings and backups are stored in Chrome on your PC. When sharing is on and you start sharing or save a change, presets and information used to check updates (a random per-PC identifier, update IDs, a hash, creation time and version) are also stored in Chrome sync on your Google account.

Full details: Privacy policy.