Check the file first
Large files, unusual formats, damaged images, and file names with special characters can cause upload trouble. Try a common image format and a shorter file name.
Check the connection
An unstable network may interrupt uploads, especially with old family photos scanned at high resolution. Use a stable connection and avoid switching networks during upload.
Try one change at a time
Resize the image, save a new copy, or upload from another browser. Keep the original photo safe while testing. Once the upload works, add a caption so the memory is easier to understand later.