Image
Convert, resize, crop and compress without uploading anything, plus the pixel and byte arithmetic around it.
Most of these open a file and a few take none at all, and it is worth knowing which is which before you click. The ones that do — the format converters, the compressors, the resizer, the cropper, the DPI checker and the EXIF viewer — read your file with a canvas in the browser and hand it straight back. Nothing is uploaded, so there is no queue, no size cap beyond your own memory, and no copy of your photograph sitting on a server afterwards.
Which ones open a file, and which do not
Among the file tools, choose by what you are optimising for. The compressors trade quality for bytes and show you both numbers so the trade is visible. The format converters change the container: WebP usually wins on size, JPEG always opens. The resizer changes how many pixels there are; the DPI tool changes what those pixels claim to be when printed, and only one of those two does anything to a screen. EXIF is the one to run before posting a photograph, because that is where the GPS coordinates are.
The rest take no file at all. Video bitrate, file size, frame rate and screen size are pixel and byte arithmetic — what a stream costs per minute, how large an export will come out, how many frames a clip holds, what a diagonal in inches means in pixels. They are here because they answer questions asked while doing the rest of this work, not because they touch an image.