Well, you can mix any image with a procedural, sure. But mangling coordinates to operate on an image is very selective and depends greatly on the type of image. For complete random’ish textures, you have to use a different approach if the image is seamlessly tileable or not. A seamless image you’re completely free. On an image with seams, you have to make sure the lookup can never exceed the bounds - which typically require a bigger image to sample from.
You can have random’ish images that have structure in one or more directions. That would prevent rotations from being utilized. Say i.e. wood grains; you can create a huge none tilable image using Skorupas wood generator, make it quasi tilable in photoshop, but it would look all wrong if you allowed rotations on various planks of a wooden floor as the grains are supposed to run in the length of the board.
And of course, you have images that you just can’t mix and mangle this way, such as those with an orderly structure to it. I.e. a pebble stone texture, where you would clearly see the blending happen - you shouldn’t be able to see the contours of one stone through another.
Lastly you have pure procedurals of mixed quality and complexity. Download some and see what they do. They are the most flexible, but the tools we have are quite limited; few useful generators require many of them and lots of time experimenting to get useful results, and disability to “expose anything” will require you to write a big library of functions in order to expose or drive values that can’t otherwise be exposed or driven (mapping node, color ramp, textures, and more). If you’re decent in maths, it will be easier to learn - I suck, so it’s taken me 30 years or so and often here it’s the maths I need help with, not the idea in my head.