Email services limit attachment size, at a size you should check with your current provider, and a handful of phone photos can reach that. Smaller photos also open faster on the other side.
Pixels beyond the width you set, a little fine detail and the metadata. 1600 pixels is plenty for viewing on screen and for small prints. If the recipient needs to print large, send the originals through a file-sharing link.
Photos of documents, children or your home are better not sent to a third-party compression site first. This runs locally.
The free Image Compressor handles 25 images at a time, with no signup and no upload.
Open the free Image CompressorThe planned $12 one-time offline pack is not yet for sale.