I'm a programmer: art is NOT my strong suite.

I have bought some cat assets from the Unity store, but I want to replace their textures with the textures from two real-life cats (it's an in-memoriam project to mod them into as many Unity games as possible, so that I can play with them again ?)

But, while I have plenty of reference photos of my cats, and while I know how to replace a texture image in an asset with another image, I don't know how to convert my photos into a high-quality skin texture image.

For this, I assume there's more than one way to skin a cat (sorry!). I can think of at least two:

• a lengthy learning curve on how I can properly skin a cat, but I don't have the first clue on how to do that; or
• pay an artist, which will likely get me a better result, sooner. But I don't know how to find an artist who could do a good job on it, nor what would be a reasonable price.

Any advice on either of these approaches to cat-skinning?

Skinning a model is binding the verts to an animation skeleton. It has a very specific definition not related to texturing.

You might have some luck googling retexture/retexturing. Mostly all you need to know is how to use Photoshop. Bring in the existing texture on a layer and match the layout to that. Many tuts only focus on recoloring the existing texture.

If the already existing texture doesn't have much of a pattern, you may have some problems matching. You could use a different texture pattern with some varitiy and put it in the game to see what goes where.

As to the second option--finding an artist--you might perhaps try this very site's “paid work” section, at the following link, I believe:

https://www.gamedev.net/contractors/​

(With the caveat that it wasn't working for me when I tried it at time of posting; however, it may be working for you, or when you try it.)

Yeah, sadly that page seems dead :(

You're right--I was hoping that the issue was transient, but it doesn't seem so. :/

Well, there are other sites that you might try! Perhaps look to TIGSource, or a dedicated site like Fiverr. (Others may have other and/or better suggestions!)