How to show Blobimage

If I have a blob image, added with 'multi field' or datagridfield (so as far as I know, I can not access it with scaling), is there a way to construct the img url ?

Actually, I can get it to render with:

<img src="${url}/@@view/++widget++form.widgets.IPhotosBehavior.image_pairs.${repeat/photo/index}${photo/filename}" />

But looks really ugly and I could only get it to render files added with multifile widget to render if the context item also had a data grid field.

I figured out how to render the multifiles:

 <img src="${url}/@@view/${repeat/photo/index}">