Nicolas,
I think the issue I am having here is related to the image width and height defined in Configuration--->Files. True dimensions of the image I have is 640x480. Dimensions I set in the Files tab for "product page image width and height" is 200x200 (attached). So when the customer clicks on the product title, he/she will display an image no larger than 200x200 but when he/she clicks on the image, the image will enlarge to its original size, that is 640x480, in the pop-up window.
My questions:
1) The image I have has rectangular dimensions. Should the dimensions I define for the "product page image width and height" be rectangular, too?
2) What other parameters (thumbnail dimensions, image dimensions etc.) should I define and how? If I need to modify any settings outside Configuration--->File tab, what settings need to be modified?
I am using the Essential version 2.0.0.
Thanks