Cratejoy templates do not currently have defined recommended sizes for your images, but there are some best practices that will help in understanding how to make the most of the available space while maintaining reasonable page load times.
Header Logo
When replacing the header logo with your own image, it should be scaled to around 320px by 51px.
Hero Banner
Most Cratejoy templates have a Hero banner image, which is intended to be a large image describing the general theme of your subscription. Hero banner images should be scaled to around 1000-1200px on the long-side. The banner image will stretch with the width of the browser window, and the banner may crop on the sides depending on the width of the screen or browser window, so you should test out your image with various screen widths.
Homepage How it Works section
If you're using Tasty, Bold, or Fashion, the How it Works Step images on the homepage are inserted into 200px by 200px containers. The As Seen In images are inserted into 250px by 250px containers, but the images do not constrain to these containers. If they should fit within this space exactly, you'll want to resize them to 250px by 250px or less.
JoyBox has similar image containers on the homepage How it Works section, and these image containers do not maintain a fixed size. The default images are around 150px by 150px.
Other Images
Smaller images, and those in other Cratejoy templates, such as the Featured icons, How it Works steps, or product images on the one-time shop page can be scaled down to around 500px on the long-side for best results.
For a more advanced overview of image optimization, see:
Image Optimization