Not true.. the IMAGE HOVER feature of Image Handler doesn't work on the medium images displayed on the product information page.. Otherwise image Handler manages ALL product and category images..
Tells me that you uploaded your main product image (the "medium image") to a folder called "
/images/medium/Jenny/":
http://leather-jackets-leather-fashion.com/images/medium/Jenny/002_MED.jpg. Your other images on the other hand are located in a folder called "
/images/Jenny/":
http://leather-jackets-leather-fashion.com/images/Jenny/002_01.jpg.
Your medium image gives one a 403 error (which is why it doesn't display). 403 error aside, the first thing that stands out for me is that there is NO REASON for you to put images in the "medium" or "large" image folders, nor is there any reason to name your files as you have done with the "_MED" appended to the file name. In fact you should NOT use these folders or naming conventions at all..
As stated frequently in this support thread and in the IH4 readme instructions, you DO NOT (SHOULD NOT) need to upload specific small, medium, or large images at all.. You do not need to upload images to the "medium" or "large" image folders, nor do you need to append "_MED" or "_LRG" ro your file names.. Upload your LARGEST IMAGE and IH4 will generate optimized small, medium, and large images for you. So I would start with removing the images in the "
/images/medium/Jenny/" folder and edit the product to make sure the largest main product image is in the "
/images/Jenny/" folder.
Secondly because of the way ZEN CART magaes additional images, you are going to need to change your image names from what I assume is the default manufacturers image names. Your images names should NOT contain ANY numbers otherwise you will find that eventually images that belong to one product will appear on other products as well..