The classifieds site seems to be picky about the size of photos and doesn't warn you when they're too big. This is an impression I've gotten from others posting about difficulties with ads and photos, not first-hand experience so take it with a grain of salt.
There don't appear to be guidelines shown in the process of making the ad and uploading the photos about what size the photos should be, so perhaps a moderator can share that info if there is in fact an upper limit.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill