When you're logged in, you can copy other posts' text.
If you search this forum for pics, and you find a user who uses your hosting provider, you'll see the code used, and you can use that as a guide to post yours.
I use 'postimages.org'; and, I've created a free account so that I may control the pics after uploading. As a 'guest', I wasn't able to find out how to delete them after uploading.
On that site, when you select a pic for posting, they have several options to copy code to direct people to that image.
I use their "Hotlinks for Forums" button. There's also an option for 'thumbnails', but for me, they're a little small for phone access.