Yes, you can include images in the body text of your questions. However, there is no way to upload an image directly onto PokeBase, which tends to confuse some people. You need a direct link to an image that is on the internet, e.g. a web address leading to an image file. Look for extensions like .png and .jpg.
For example, the web address of the Salamence artwork on its PokeDex page is this:
https://img.pokemondb.net/artwork/large/salamence.jpg
I can use Markdown syntax or other techniques to tell the software to show the image in my post. You do this the same way in a question as you would in an answer. This post and this post contain steps for the multiple ways you can do this. It should be very straightforward if you click the photo icon above the text editor and follow the instructions.
If you have an image on your computer that you want to put in your post, then you need to upload it to the internet in order to link it on PokeBase. You can use a free and anonymous image hosting website like Imgur to upload your picture, and then you can add it to your post. If you're having trouble attaching the image directly, just supply a link to the album and somebody else will do it for you.
