You can try to use gyazo, otherwise you can hit "preview" on your forum post before you submit it so you can make sure your images are appearing..
Greetingsnya! I love using imgur for showing posts! Upload your image to imgur and when it finishes uploading, click on the 3 dots and click get share links. Click on the BBcode (Forums) link and copy it. Those should make the images pop up. I bet those images are great! If you don't like Imgur, try to make sure your image is .jpg or .png. Good Lucknya!