SEO for Pictures

So I have a blog that is being updated daily, I use 3-5 pictures per post and always pay great attention to optimizing pictures, I name them with my keyword and put the same k/w as alt-tag. Mostly every picture represent different product, but sometimes one post covers one product, so what would be the right thing to do with the keyword that I use? Should I use the same k/w 3 times or it is better to use different? I got very good traffic coming from images (google search>images), but still some posts perform better then the other and for some specific products I just can find only 1 kw....so what would be the best? I guess if I add 1 (number) at the end of k/w that I put in name and alt-tag won't do any good?

Setting featured images and connecting proper alt tags, both of which can be done with Wordpress plugins makes image ranking a much more simple process.

Other than that just do SEO like you normally do with adjusted social signals to top it off.

Not sure that this answers my question though

The whole premise behind 'alt tags' is that they are meant to be there legally - as people with disabilities that use 'screen readers' and 'voice to text' use the alt text description to figure out what the image should be.

Thus we should be naming alt tags to what the exact name of the image is in a way that will inform someone who can't actually see it - not just a generic duplicate name.

In the case of multiple product shots, I can agree that gets a bit tough - in brief; try to make it user-friendly as much as possible and use different adjectives for the product names in the alt tags if possible.

It's better to use different KW's for as you have already get traffic for a KW in google images.