photon can't be turned off

Once you have turned off the Photon Module in your Jetpack menu, your images should be served from your own server again.

However, it’s worth noting that if you use Tiled Galleries on your site, the images will be served from WordPress.com, as the image need to be resized on the fly to create the tiled effect.

If other images are served by WordPress.com on your site, could you post your site URL, and give me a few examples so I can have a look?

Thanks!

WordPress has its own resizing mechanism, right? Even with non-title galleries, the thumbnails are generated directly within wordpress, why can’t this happen for tiled galleries?

WordPress and Photon work differently. When you upload an image to your WordPress site, WordPress crops, resizes and creates new files for each image size you have specified.

Photon, however, resizes the images on the fly, without creating new files: this way, the look of the Tiled gallery will always match your theme’s content width, because the width of each image, and the arrangement of all the images is done when you load the page.
That also allows you to use the “Random order” option in the Gallery settings, thus creating a new Tiled gallery each time the page is loaded.

You can read more about Tiled Galleries and Photon here:
https://jetpack.me/support/tiled-galleries/
https://jetpack.me/support/photon/