I see yours here is about 340 pixels wide. If you can get them off your camera or photo software at about 1000 pixels wide, that can usually upload here. If it's above 100 kb memory, you can try "save as" which could allow you to lower the file size? If not, there may be a sizing tool in your software.

It's easy to advise somebody but not knowing what you have to work with, it may be of little help.