You're asking the wrong person. Due either to my client, or my instance, I get, like, a 20% success rate on attaching images. Most of the time I get an error.

On my client, there's a little picture icon. When I click that, it lets me select a picture and, if the wind is blowing in the right direction and the stars align, the picture is embedded. Otherwise, I upload to catbox.moe and manually embed the URL. The markdown syntax for an embedded image is:

![](https://url.ofyour.pic/thing.jpg)

On desktop, you can just paste it.

You can do markdown, so ![](https://link.to/image)

i usually just have the picture in my clipboard and then ctrl+v. it should be uploaded and the markdown link added for you

I use Jerboa client on Android. It feels very much like the Reddit is Fun app.

There are rich text buttons at the bottom of the new post field. One is a photo icon, click that and it takes you to your photo/file browser to select a pic.

Here's a pic I took of Earth's bff, la Luna.

If you’re using voyager you can just copy and paste and it will handle it, usually, assuming your instance has image uploads enabled.