I'm a developer and I've modified a little bit the related plugin to suit the design of my client and I have some questions. Basically the thumbnail size is 190 x 190px and the uploaded thumbnail is 150 x 150px, so there is a pixelated problem. It's a way that you offer custom thumbnail size on your CDN? Or else do you support that thumbnails could be loaded from the localhost. What I'm trying to achieve is to put some 190 x 190px images on the page, but with thumbnails that are at the 380 x 380px (retina 2x).
Also where to put the new css content so that will not be overwritten with the next update? (I've have not find a tutorial page about your plugin to do so, only some second part on how to edit and use some default classes, on your blog)