Primarily photo and video editing software are CPU intensive. Classically an Intel CPU would have been your best bet, but AMD has closed the gap on single core performance so much that it doesn't really make a difference. What will make a difference is core count, and AMD will give you more cores for the money.
So, CPU definitely would make for the biggest upgrade. Depending on what codec you use for video encoding your GPU may or may not want an upgrade. If you are using software rendering and encoding then the CPU would be the only thing being used, if you were using NVidia's hardware encoding, then an RTX 2060 would be a great upgrade as it includes NVidia's latest hardware encoder technology, which is actually pretty good.
Depending on the size of videos you edit a RAM upgrade might also help out a lot. This isn't so much an issue with pictures as they require a lot less memory for manipulation.
A storage upgrade only makes sense if you do a lot of reading and writing to the drive and you end up waiting a long time for those operations to finish. Normally that isn't a problem for video or pictures as they load to RAM, get edited, then get written to the drive when you save, unless you are trying to edit huge files and you don't have enough RAM to load them completely into memory.