What are the limits of size for the images?
It is not recommended to add images which are too heavy in your online store, because they are slow to load and it slows down the site navigation. Visitors are impatient and they might leave your site if it is too slow to load.
Furthermore, it is not necessary to have high-resolution images, because browsers (like Internet Explorer or Mozilla Firefox) will use the images with a very low resolution.
Below are the size limits for images :
Little image of product : 50 Kb
Big image of the product : 300 Kb (this includes zoom and mini images).
Image logo of your company : 20 Kb
The maximum weight of each image in the articles should not exceed 150 Kb.
Total size of images in a static page (like the homepage) : 1024 Kb