@Sandisw I know you are having trouble with your signature image, so let me know if I can help.
I saw you mentioned you put your image into a test post and I looked at that post and it's not visible there.
You can use this thread to try also if you want. I'd start from the beginning again, since the image isn't appearing, however also look at what VGCgroupie said as she had an issue because she was copying the image address from the web browser bar but not grabbing it from "copy image address" like in my screenshot. Possibly that is what is happening for you?
1. Find a thread to reply to (you can use this one or any other) and either paste the image into the reply or click the insert image button and select your image. Then click Post Reply. This will get the image into the DisBoards system so you can add it to the signature later. The image may be larger than you want for your signature- no worries, you can adjust the size when it's time to insert the image into the signature section.
2. After you click reply with your image inserted, right click on the image in the post. Then click Copy Image Address. This copies it to your clipboard. If you are wanting to use a graphic that another DisBoarder has allowed for others to use, right click on the image and click copy the image address.
3. Proceed to the next tutorial section to add image to the signature.