I found an easy way to resize photos that are acceptable for uploading to the QB that works for me, and thought it might work for you.
I email the photos I wanted to upload, to myself. Then I save that version on my computer.
When I attached them to upload, they upload fine. Didn't get the "failed" message that often comes because the size is too large.
It seems that my computer is automatically resizing them for acceptable file size by emailing. (I bought a new camera with 12 megapixels, which is certainly too large to upload to QB.)
Hope this works for you!