iMac screen issue - red stripes

Hello,

Upon returning to my iMac after a break and waking it from sleep it only displayed red stripes on a red background. Restarting the computer seemed to solve the issue, but after waking it from sleep another time the issue seems to be permanent. I have tried resetting SMC and NVRAM but neither have worked. Anyone familiar with this issue? Picture linked for reference https://i.imgur.com/JtYX8bP.jpg

Welcome to our forums.

You didn't mention which iMac you have (year and model), but the screen shows a classic case of the graphics card having failed or failing. Some iMacs have a removable graphics card which can be replaced, others do not. Either way, it's a very expensive repair. It's possible you may be able to find someone who can reflow your graphics card or replace it. Doing the job yourself is very difficult.