Robert Cargill has made a video that demonstrates, step by step, how to correct the perspective distortion of the high-angle camera shots of the so called "Fish" on the "Jonah Ossuary":
It's nearly a half hour long, but it's rather thorough.
I've been working on a similar perspective correction illustration by aligning the features of the drawing relative to its "canvas" (i.e. the size and shape of the ossuary itself).
I first started out with image #14 from the "The Jesus Discovery" website as it is so far the most complete of the pictures released.
It may be labeled "no CGI" but that's a little bit of a fib. As we've seen from other images of the ossuary, this nice, uniform sepia tone is not the actual color of the artifact. This image has been put through a filter or two. But never mind about that. :-)
I essentially mapped out all of the perspective-relevant features: Lines that should be vertical and horizontal relative to each other, and then I mapped the "grid" that was created as flat as I could.
It's not perfect, as there is a little bit of distortion from the lens they used (in my next iteration I'll see if I can fix that) and I need to expand the right hand side a bit more; however, we can see that when the features are more or less aligned relative to each other, and the final frame is re-sized to something the proportions of its place on the ossuary, we get something very vessel-like, and not ichthymorphic at all.
The rim is as wide as the hip of the vessel and "Jonah's head" is flattened to a half-spherical base.
Since Bob was able to do this with one image, and I was able to do this with another, my haphazard guess is that if every photo of the "fish" we have was adjusted for perspective, it'll end up looking similar to this as well. :-)
UPDATE March 23: Some additional illustrations for my discussion with Dr. Tabor in the comments.
This illustrates how image #14 (on the bottom) is filtered compared to the "raw" image #15 (on top) where both are labeled "no cgi."
This illustrates how the reproduction ossuary did not capture the proper shape of the head/base.