SEO - picture seofilename

Hello,

My seofilename for the picture is the product name (which is the part name) and I would like it to be more descriptive and SEO friendly.

Is there any risk if I concat the seofilename so that includes the part number and the short description provided the seofilename is seo friendly (ie: no spaces, etc and proper string length?

Where does the ALT IMG name get picked up from?

Thanks much
Dave