Normally these are for saying "Thx 4 the add" or maybe for your profile idk?
Mk anyway search up anything on google and make sure It's a gif
Next right click it and copy image address link
After just edit and paste the image address either on your "about me" or "who I want to meet" or sum.
Mk thats all
I forgot to mention sometimes they don't work probably bc you did sum wrong or it just doesn't
google images can dissapear often so i reccomend upload it to discord or imgur and copy from there if you want it to last forever