Adding photo credits/captions

We’d like to include photo credits for images placed in blocks in the header first area. Adding it as a <p> below the images, it shows but we have no control of size, placement. Whatever we throw at it CSS-wise fails. The other thing we’ve tried per the instructions, is adding the credits as titles under advanced in the image dialogue. But this doesn’t work and we suspect it is beacuse the block is not in the content region.

Is there a simple way to do this — ideally so that it would locate in the lower corner of the images, at a small size, with CSS?

Thanks,
Bjorn