New to Blender so this is a newbie question…
I’ve attached an image of a texture I’m using, but it shows shadowed lines all around the texture. Where can I change the setting to delete those stripes?

Those just look like normal viewport shading artefacts. They should go away once you get to rendering.

I’ve rendered it, but the artefacts were still visable. However, I opened the rendered photo on another screen and they are not visable. I guess it has to do with the (old) graphic card on my computer.