If you are looking for a "good guide" on how to handle these files or find more like them, here is how to navigate these specific assets:
For example, image hosting platforms like Wallhaven use specific resolution tags (955x1350) and unique ID strings to catalog portraits, such as popular fan art of characters like from Kaguya-sama: Love is War . How to use these strings effectively 955x1350 Originals 44 57 4e 44574eded6de37d">
You can take the hex code or the image itself and use tools like SauceNAO or IQDB to find the original artist (the "Originals" source) and higher quality versions. If you are looking for a "good guide"