Btw: I couldn’t upload the picture to Lemmy directly, as it’s probably too large for my instance limits. But I’m not sure which image sharing platform is still ok to use (after imgur) and I’m even more stuck in how to embed the linked image correctly in a comment, besides just linking to it.
What’s the correct way to do this?
You might be better off learning to use an app or editing to crop and then swap old image formats to webp in order to get them much smaller. In Linux it usually happens automatically by just renaming the file from something like .jpg to .webp.
I would have grabbed the image to post it as an example but the postimg host is a mess of a website I don’t let through my firewall (IIRC from the last time I tried). I don’t think they allow direct embedding either, thus the reason their website is such a convoluted mess of junk happening in the background.
You could sign up on a Pixelfed instance, or self host if interested as that is part of the fediverse.
The image embedding syntax on Lemmy is 
changing the file extension shouldn’t do anything, especially on linux, maybe if you’re using a distro designed to do that. It will just pretend to be a different format, and if it works its pure chance, because file extensions don’t really do anything. I’ve had a lot of jpgs that weren’t actually jpegs and were actually pngs but they were listed as jpg for some reason, shit is just silly.
Anon is a Butt Wizard I think is what you meant
I’m having the perfect T-shirt for him
Btw: I couldn’t upload the picture to Lemmy directly, as it’s probably too large for my instance limits. But I’m not sure which image sharing platform is still ok to use (after imgur) and I’m even more stuck in how to embed the linked image correctly in a comment, besides just linking to it.
What’s the correct way to do this?
Trying to embed the image:

catbox.moe might be an option.
You might be better off learning to use an app or editing to crop and then swap old image formats to webp in order to get them much smaller. In Linux it usually happens automatically by just renaming the file from something like .jpg to .webp.
I would have grabbed the image to post it as an example but the postimg host is a mess of a website I don’t let through my firewall (IIRC from the last time I tried). I don’t think they allow direct embedding either, thus the reason their website is such a convoluted mess of junk happening in the background.
You could sign up on a Pixelfed instance, or self host if interested as that is part of the fediverse.
The image embedding syntax on Lemmy is

changing the file extension shouldn’t do anything, especially on linux, maybe if you’re using a distro designed to do that. It will just pretend to be a different format, and if it works its pure chance, because file extensions don’t really do anything. I’ve had a lot of jpgs that weren’t actually jpegs and were actually pngs but they were listed as jpg for some reason, shit is just silly.