So here's my problem: I have a site with several articles on the homepage, these are using the featured image as a thumbnail (roughly 250x250). Then, for a single article (single.php) I'm using the same image (with the same call get_post_thumbnail). The issue is, I don't need to be loading 1600x800 images for thumbnails, but I do for display on a single article.
I've looked in to plugins like Multiple Featured Images so I could just have 2 different sizes of the same image, but this would require me to go back through every article and upload a scaled down image.
Basically, I want to upload one image, but use 2 different sizes of it for site speed reasons.