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When you are going after long tail traffic the queries that you might connect with are  A) infinite in number;  B) diverse in their wording;  and,  C) extremely low in volume. Because long tail word sequences usually have a low volume it is best not to fuss about getting    precisely    the     right    word   sequence.   Instead, it is best to write using natural language. It is more important to increase the diversity of words on your page.  You can do that by writing about paintings of mule deer for your den, framed prints of whitetail deer on the edge of a cornfield for your office,  matted photos of fawns in the laurel for the nursery, a water color of an eight point buck by the lake for above the fireplace at your camp.    Note we are diversifying the deer, their environment, the room where they will be displayed, the medium and the mountings -- all on the same page. This diversity allows you to present a substantive article that will be qualified to appear in search for an enormous number of keywords and even though you never mentioned exactly a "framed painting of an eight point whitetail for your den" on this page, if someone searches for it this page of content is qualified to appear in search for it and if your website has a little power, this page might rank well for it. Also, people buying paintings might shop deep into the SERPs or view the image results.  So even if you are not at the top of the first page of the SERPs you might still get some action.  And, load pages like these up with a number of images because image SERP shopping can pull in conversions for this type of merchandise.

I agree with DC1611 and would reiterate you shouldn't just stuff your keywords into both tags. Google's penalized keyword stuffing for some time now and they are always emphasizing user experience. Remembering that alt tags are designed to help visitors who are visually impaired and given the space constraints of title tags, I'd err on the side of using language that succinctly and accurately describes the image.

I agree with Dirk - the names you have suggested would work fine and there is a clear difference between each. Obviously the more descriptive you can be with each file the better - but often easier said than done on eCommerce sites.