[REQUEST] More Concise LockScreen README Wording

Is your feature request related to a problem? Please describe.
I want to apply a lock screen to an ISO build and I find that the README is vague in its instructions. The README says that it must be a JPG though it doesn't specify if it can be a progressive JPG or not. Additionally, where it says that the image must "have dimensions appropriate for the resolution (1920x1080)", it makes it seem as though I need a 1920x1080 JPG though I have doubts as I'd assume 4k JPGs should allowed. It is unclear to me as to whether or not 1920x1080 is the minimum requirement or if I can go higher.

Describe the solution you'd like
I would like to see the README elaborated on more clearly as I find myself confused when it comes to converting the wallpaper I plan on using to become the lock screen image.

Describe alternatives you've considered
N/a

Additional context
N/a

Update: After attempting to run Optimize-Offline with a 3991x2245 JPG wallpaper (I can't remember if it was progressive or not) it seems to have worked out fine. That being said, I still feel as though the README with the "dimensions appropriate for the resolution (1920x1080)" is misleading and should be better elaborated on further as it still comes off as kind of vague.