Image Lightbox
Open images at a useful size without sending users to a raw file URL.
What it adds
An overlay viewer that shows an image at full size with zoom, keyboard control, and a clean way out.
What your agent is told to do
6
What your agent is told to do
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1
Open the viewer as a modal layer with focus trapped inside it, and return focus to the thumbnail that opened it on close.
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2
Support Escape, a visible close button, a click on the backdrop, and the browser back button. Back must close the viewer rather than leaving the page.
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3
Show the low-resolution thumbnail immediately and swap in the full image when it loads, so the viewer is never a blank rectangle.
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4
Support pinch and double-tap zoom on touch, and keyboard zoom and pan on desktop, with a reset to fit.
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5
Do not load the original file at full resolution on a phone. Request a size appropriate to the viewport and device pixel ratio, or a large photo will exhaust memory and kill the tab.
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6
The surrounding file list, ordering, and captions are owned by Attachment Gallery; this feature is the viewer only.
Edge cases it handles
6
Edge cases it handles
6- A broken, deleted, or still-processing image must show a clear state inside the viewer, not an empty overlay or a browser error icon.
- A private image whose signed URL expires while the viewer is open must re-authorize or fail with an explanation.
- Background scrolling must be locked while open, and restored to the same position on close — including on iOS, where this is not automatic.
- Swipe to dismiss and swipe to pan conflict once zoomed; dismissal must only apply at the default zoom level.
- The image needs its alt text carried into the viewer; a decorative thumbnail becoming a focal image without a description is a regression.
- Very tall or very wide images must fit to the viewport on open rather than opening at native size.
Definition of done
9
Definition of done
9- Focus is trapped while open and restored to the trigger on close.
- Escape, the close button, the backdrop, and browser back all close the viewer.
- A placeholder or thumbnail is visible while the full image loads.
- Zoom works by pinch, double-tap, and keyboard, with a reset to fit.
- Requested image size is bounded by viewport and device pixel ratio.
- Broken, private, and processing images each have their own state.
- Background scroll is locked and restored exactly.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Beautiful Empty States
Beautiful Empty States
Replace blank screens with useful, contextual empty states.
What it does
Every list, table, and dashboard in your app has a "nothing here yet" state. Most
apps ship a blank rectangle — and it is often the very first thing a new user sees.
An empty state should say what belongs here, why it is empty, and what to do next.
How it works
- 1 Inventory the empty cases first. List every collection view in the app and
- 2 Distinguish the three kinds of empty. They are not the same, and must not
- 3 Build one reusable empty-state component from the existing design system,
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/beautiful-empty-states
Opening Hours Display
Opening Hours Display
Say whether you are open right now and when you next open.
What it does
A live open or closed state alongside the weekly hours, with holiday closures folded in.
How it works
- 1 Lead with the current state in plain words and follow it with the next transition: open until a time, or closed until a day and time. The weekly table is supporting detail, not the headline.
- 2 Store hours as intervals against the business's own zone, and keep holiday and one-off closures as overrides that win over the regular week rather than as edits to it.
- 3 Compute the state on the server for the first render so the page does not briefly claim the wrong thing, then let the page update itself as the clock crosses a boundary without a reload.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/opening-hours-display
Dark Mode
Dark Mode
Add a dark theme that respects the system preference and the user's choice.
What it does
A complete dark theme, defaulting to the operating system preference and overridable by the user.
How it works
- 1 Audit every colour in the app first and report where they are defined. If colours are hardcoded throughout, extract them into tokens before anything else — that refactor is the bulk of this work.
- 2 Define a dark palette against those tokens. Do not simply invert the light theme.
- 3 Default to the system preference via prefers-color-scheme, and let the user override it.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/dark-mode
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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3
It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.