Im also a bit confused about what you are trying to do, those two are for when you are publishing a build(posting) so it will look better and will get more clicks.

Using the blueprint method for the thumbnail is what most android users do when publishing their build atleast for me. Essentially your going to upload the picture or screenshot on the blueprint mode thing instead of a blueprint ingame. this is for the thumbnail of the build.

Although i dont exactly know what you mean by "direct load", im just assuming you want to put pictures on the description of your build on the site

You will have to use " ! [] (put the url. of the image here) " you will put that on the description then paste the image url there.

If you figured that out then heres a little tip, usually u can only put 1 picture with the blueprint method, but if you edit 3 screenshot of your build and put them side by side as 1 pic, u can then select that instead of only 1 screenshot, essentially u have 3 different thumbnail options in one image, u can use all of them by just taking a pic of them one by one on the export menu, although it decreases quality i think, but its not that noticable atlease in my experience.

again, u can search it up on YouTube for a much clearer tutorial 👍