The Product Hunt thumbnail size
The Product Hunt thumbnail is the square image next to your name in the daily list, in search and in the newsletter. Product Hunt recommends 240 x 240 pixels, and an animated GIF is allowed. It is shown small, so it has to read at a glance.
How to make a good Product Hunt thumbnail
Use your logo mark, not the full wordmark, with enough padding that it is not cramped when shown small. If you use a GIF, keep the movement subtle and make the first frame work on its own.
Questions
What size is a Product Hunt thumbnail?
The Product Hunt thumbnail is the square image next to your name in the daily list, in search and in the newsletter.
Can the Product Hunt thumbnail be a GIF?
Yes, an animated GIF is allowed. Make sure the first frame still looks good, since some places show a still.
Is my image uploaded anywhere?
No. The image is read and resized in your browser; nothing is sent to a server.
How does the resize work?
It scales the image to cover the target size and crops the overflow evenly from the edges, so nothing is stretched.