Image sizes clutter

How many and what exactly image sizes does the theme produce?

My site is configured to have only original size pictures and thumbnails of 150×100. I know that the theme makes carousel size 600×400. But on top of that I now get the clutter of multiple files.

It turns out that the theme makes not only carousel-thum of 600×400 but a featured image thumb of 640×420. I don’t use featured images in the body of the post though, only as featured images in carousel/homepage/archives lists. The problem is that both carousel and featured images (I mean those shown in widgets on the home page) are actually shown smaller than 600×400. You can see it sometimes when there is a slight delay in loading – firstly the big 600×400 or 640×420 images are loaded and then they are adjusted to their smaller screen#homepage positions in the carousel. Why make the theme cut bigger images and make the homepage load longer then? Why cut a big carousel image file when it wil be shown at a different size anyway?

But this is not all. It turns out I also end up with strange files: small thumbnail 100×100, rectangle 220×130, medium-thumbnail 200×200, large thumbnail 400×400. Plus there are wpmobi-new-thumbnail: 92×92 and mobileview-custom: 100×100 (the latter being the same file as the small thumbnail mentioned above) which I guess are created by the mobile-theme plugin.