If you are using Chrome then right click your gamercard -> Copy image address then put the link in your profile summary.
But again, just shows as a link and won't display the image itself. There doesn't seem to be anywhere you can put images on Steam unfortunately
![Frown :( :(](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f641.png)
There have been some rumors of an interface revamp, so maybe this will change eventually.