If cyphertext in image metadata would be acceptably well-hidden, this should be as well: you can hide four bits per pixel using the least significant bits of the RGBA channels. A human won’t be able to tell the difference between #FE007BFE and #FF017AFF.
(This assumes .png. I don’t think it would work very well, if at all, for either jpeg or gif.)
If cyphertext in image metadata would be acceptably well-hidden, this should be as well: you can hide four bits per pixel using the least significant bits of the RGBA channels. A human won’t be able to tell the difference between #FE007BFE and #FF017AFF.
(This assumes .png. I don’t think it would work very well, if at all, for either jpeg or gif.)