Quite simply, it can't hurt.
Search Engines read the code of your site.
Where a use see the image. The search engine see's.
Code:
<img src='../images/imagename.jpg' />
That will output an image with no affect on seo.
Code:
<img src='../images/brandname/productname_0.jpg' alt='brandname product name' title='brandname product name' />
That will output an image but everything in bold adds towards your SEO.
Haven't checked but if at present you have poor SEO results then hire someone professional to completely rebuilt the system to automate these types of things. Pure and simple because it will more than quadruple your keywords. If you have great SEO results at present, then just change in future.
Hope it helps
EDIT: In regard to background images, file paths etc the theory is the exact same. Image was just a simple method to show an example.