Check whether a PNG has a transparent background, count fully and partially transparent pixels, and preview it on a checkerboard or solid colours.
Crop PNG, JPG and WebP images by dragging out a selection. 1:1 / 4:3 / 16:9 ratios and custom output sizes, with PNG transparency preserved.
Images are the file type most likely to carry personal information: scans of ID cards and passport photos, pictures of a house with the number visible, unreleased design drafts, screenshots of private chats. A conventional online image tool has to upload all of that to a server and send it back — and you have no way to confirm how long the file sat on someone else's machine, whether a copy was kept, or whether it was fed into a model. The tools here do everything locally with the browser's own Canvas API, and keep working after you disconnect from the network once the page has loaded — that is a claim you can verify yourself, not a promise you have to take on faith.
Cropping is the step you reach for most often: a screenshot caught too much and the edges have to go, an avatar needs the middle square at 1:1, an illustration has to be 16:9 to line up with the layout. Transparency checking answers a different question — after you cut a subject out, a white background and a transparent one look identical in the preview, right up until you drop the image onto a dark slide and discover a white rectangle. The checker counts fully transparent and semi-transparent pixels and offers a checkerboard plus several solid-colour backdrops, so you can see the problem before you download.
Cropping supports PNG, JPG and WebP. PNG keeps its alpha channel; JPG has no transparency at the format level, so exports are filled with white. Transparency checking is PNG-only, because JPG simply has no alpha channel — the answer to "does this JPG have a transparent background" is always no. Neither tool caps the file size; the real limit is your device's memory.
Both pages are laid out for mobile — just open them in your phone's browser, pick an image from your photo library and save the result straight back. The crop selection supports touch dragging and pinch zoom. If what you actually need to handle is Markdown, a PDF or a video clip, the site has a category for each of those, reachable from the footer.