Photo tools are the category where uploading matters most and is questioned least. A holiday snapshot is harmless; a photo of a document, a product shot before launch, or a picture taken at home with its GPS block intact is not. These tools never send the file anywhere, which also means there is no upload limit and no waiting in a queue.
Between them they cover the jobs that come up again and again: make it smaller, change the format, remove what is hidden inside it. Each one processes as many files as your browser can hold in memory.
Questions
Can I process several images at once?
The resize, convert, compress, metadata and HEIC tools take up to 30 files per batch and apply the same settings to all of them. The cropper and the video-to-GIF converter work on one file at a time.
What happens to image quality?
Resizing and converting re-encode the image, so JPEG and WebP output depends on the quality setting. PNG output is lossless. In the resizer, the longest-side mode never enlarges an image, because that adds pixels but no detail; the width, height and exact modes will, if you ask for more pixels than the photo has.
Do these work with HEIC photos from an iPhone?
The HEIC to JPG converter does; it decodes HEIC on your device in any browser. The other image tools rely on your browser's built-in codecs, and Safari is the only current browser that decodes HEIC; in Chrome, Edge and Firefox, convert first or set your iPhone to Most Compatible under Settings, Camera, Formats.