bug with chome and popups

bug with chome and popups

Hello,
I found this bug and I wonder if anyone else has experienced it.
I have a popup with only an image inside; the image is inserted in the code, it is not a background image.

With Firefox, by clicking on the link that opens the popup, everything is fine. In Chrome not, it is like it is not calculating correctly the size of the image. I have to adjust a bit the size of the window and the image in the popup appears.
This happens only the first time the popup "open", the second time it opens fine because probably the size has been calculated the first time.

This is quite annoying, apparently the only way to solve this is to assign width:100% to the image; I don't like to be forced to add this however.

Does somebody have some good ideas?

Thanks