Mac or Windows? I don't know Mac... in windows, you can Open "Paint" - within the Paint program, you want to open (one at a time) each page. (if you can not locate the file, let us know)
Then go to "File" and click on "Save As" (keep the original and make a copy of it), Give it a new name (the program will reduce the size automatically - usually). You can manually, tell Paint program to reduce the size... but let's try without the extra step.
Do ONE at a time to see if it works, if not, plan B... reduce the size.
How big is the original file??? (how big is it, in Megs?) (if you don't know how to find out,, just ask again.)
Have you tried to load ONE of them at a time (each photos is a new post?) That might do it...
Report back, let us know....