...Why? Should I switch to Google? This seems to be a recent occurance. I used to do all my searches on Yahoo but if they're limiting or frontloading one source I've little use for them.

All yahoo photos are being moved because photos.yahoo.com is phasing out. Flikr is run by the yahoo photo folks I believe... if you go to photos.yahoo.com it should tell you about it... I have pictuires on there and it gives you four options to move them but flickr is the easiest. Hope this helps.
Also recently I have found it the easiest to search for any pictures I need (as I am planning my wedding) at photobucket.com

Any web search Bar is about the same, l look on the google search images and they are not no more the best on google as yahoo.So when l look for images l look on both sites,And the Home page has nothing to do with the search.
To change to google is your option.

Google has been consistantly better for me than yahoo