Search returns posts based on file url

The search form on my site (www.onceuponasidewalk.com) is returning posts based on strings found in the image file’s url.

This normally wouldn’t be a problem, but my posts are image based and designated by numbers. If a user wants to easily navigate to post/image #7 and searches for ‘7’ then it will return any post that has an image with a 7 in it’s file url.

Is there a way to tweak this so it doesn’t function this way?