Hi,
Oh, ok.
I thought you were talking about a custom field of the type "AJAX image" since you said in a previous message here that we were indeed talking about a "AJAX Image" field. But on your new screenshot, it's the "Image" type, which is completely different.
I see what you mean now. Indeed, we could add a bit of CSS by default to avoid this. Thanks for your feedback. I'll do that for a future version of HikaShop.
Ideally, you just want to use the AJAX Image type, which is better in every way.