I mean, not zoom in on a photo in Photoshop, but create a zoomed version of a photo using the same size dimensions. Is this possible? I know it will get more pixelated, but I thought there might be a certain threshold I can zoom it to. It's a photo of a bug, and I just want to make it a little larger but keep it within the same dimensions...
Be aware that any increase in size will result in a loss of resolution and sharpness. Depending on your source file and your final output needs, you can make a new document with the same dimensions but a lower resolution and place your original file in that document. If your original is, say, 5"x8" at 300ppi, you could make a 5"x8" document at 200ppi, drop in the original and then scale down until it's framed the way you want.
It is easier to destroy than to create.
More fun, too.