Thank you so much! I got some problems tho.
I have spawned the enity using ulx ent. While doing that I got "ERROR: Trying to derive entity sent_cdp from non existant entity base_gmodentity".
Ignoring the error I was able to put the image address and the enity turned blue, however I had no apply nor save button. Maybe it is a resolution thing.
Additional another person managed to save it using default img presented in the addon, however it did not appear on the wall, but after server restarting it appeared on the other map where it was never spawned.