This error occurs when enter into some sub menu entry after I use the sleek theme for Grub2, and I have tried different size of PNG images trying to avoid image scales to prevent this error message but all failed.
I searched a lot, but there is few information about this issue. One of them is https://github.com/sandesh236/sleek--themes/pull/4，and it mentioned about replacing a color setting into a image fixed it. but it indeed seems like some workaround of Grub's issue. So what is the correct way to avoid this error message? Or it is just a bug of Grub2?
