I want to combine two different pictures on postimages and make them into one picture, but I have no idea how to do that. Help, please

you'd need to do that in an art app, not postimages. for something simple like that, I reccomend the site Kleki, no download needed :)

Can free accounts sell artwork

yep :)

Trying to put my stable name/number on the artwork, but it is fighting me, thinking I finally got it to work, hopefully. Wondering if anyone would be willing to help me with putting wings and credits on this wip, before putting it up for sale in my art gallery shop. https://postimg.cc/7fWty1MD. Whoever helps me with my artwork will be greatly appreciated and will get a share of the profits