Tak, wg dokumentacji – albo-albo:

http://join-lemmy.org/docs/users/01-getting-started.html#start-posting :

To do this, click the button Create a post in the sidebar. Here you can optionally supply an external link or upload an image.

http://join-lemmy.org/docs/users/02-media.html#images-and-video :

Lemmy also allows sharing of images and videos. To upload an image, go to the Create post page and click the little image icon under the URL field.

Dzięki za wskazanie!