I thought I would share the answer I gave to a question someone asked in the Facebook WooCommerce group. They asked what people’s average file size was for their product images.
I answered that you have to start with the pixel dimensions, otherwise you are not comparing like with like. For the same image compression, an image 600px wide will usually be smaller (fewer KB) than an image 1000px wide. I say ‘usually’ because for a given compression, a photo of a tree with thousands of leaves will not compress to as small a file size as a brick wall. My single product images are 800×1133 and I compress at about 43% and the rough average of the file sizes is about 90KB, but there is a wide spread and they vary tremendously from the smallest to the biggest file size.
If this topic interests you, I wrote about pixel density for print and screen here, and I wrote about uploading images for the screen here.
For a deep dive into file sizes, with examples, take a look at this article.
Photograph Works 