I am using mac pro 13.3 High Sierra, tried to change the background to my own one but I can't as it is said that I have to make sure my device meets specific requirements however mine is as follows:
Operating System—macOS High Sierra (version 10.13.6) and later:
Processor: Intel Core i7 3000 series dual-core processor or higher
Memory—8 GB or more of VRAM for dedicated GPUs
Please help