I miss that feature so much in Substance Designer . Asked them for decade to do it . So we could import a plane and squeeze it for some 256x2048 texture preview without searching through hard drive.
And also thanks for letting drop a packed texture and use a selected channel as roughness, metal etc without any extra tricks
I bought Marmoset just because of those things . Hope to find more of a kind . I am so tired of Allegorithmic products. They seam just doesn't understand what simple and easy to use tools are.