png files appear differently

 These are screenshots of an image of a blue bag that was edited in photoshop.  The image was exported as .png with a transparent background and then uploaded to two different places in my online store.  As you can see below, on the product page, the image appears on a transparent background. However, on the store's category page the image background is distorted. I opened the exported png in photoshop. The image layer's thumbnail now appears to have the same distorted background that is visible on the category page.  Help! This is happening on multiple images.