Depends on your budget, editing software and if you want to play games at 4K also.
For photos; Photoshop and GIMP are both GPU accelerated. So the faster the GPU and more GDDR it has the better.
Video transcoding, however, tends to be CPU bound and the i7 you mention in another thread should have no problem.
If you're not playing PC games, or are happy to play them at 1080p, a mid-level card from either NVIDIA (e.g. GTX 1050Ti) or AMD (e.g. RX 470) should see you good. Expect to pay 1800 - 2500SEK for the two cards mentioned.
Please make sure you check the amount of GDDR it has... Photoshop will perform a lot better with a 4GB card, than a 2GB version with the same GPU. And for what you are using this for it is worth spending the extra 300SEK to get a 4GB model over the 2GB model. (Whether it's worth spending the same again to get an 8GB model is up to you.)