In OrderStorm Sys Admin go to SETTINGS > STORE SETTINGS and click on the PRODUCT IMAGES tab. There are 4 “image layers” for each product. The first layer is the image that is displayed for the product when the product is listed in a category. The next 3 layers are for the image gallery on the product detail page (the page that shows all the information about the product). Out of the 3 images payers one is for the settings for the thumbnail for the gallery, one is for the preview image for the gallery (the main image in the gallery) and the last is the image that is displayed when your customer clicks on the preview image or the zoom image.
Some of the settings are for the size of the images. You can set the length of the longest side, the width or the height. You may also have to make a change to the template of your HTML page in WordPress to make size changes. Some templates will have the space/size for the image already predefined.