I took a look at your account and saw that there was an image uploaded on the day that you posted this message. It look like you may have been uploading PDF versions of an image, which show only within the Document library. In order to insert a file into your email so that it displays it does need to be an image file type (png, gif, or jpg). If you need any help with Converting an image file, take a look at this post here with instructions on how to do so using a screenshot.
If you need any other assistance, please let us know.
Thanks for posting, I am sorry to hear of this frustration. When you upload a PDF it will show as a document in your library so you won't be able to insert it as an image. If you wanted it to show in your email you would want to convert the document to an image file instead. There are free online converter tools that would do this for you, just google for one. Please note, these are not Constant Contact products so please use at your own risk.
If you are okay with the PDF only being linked in your email you will want to choose to insert a document link on the left instead. This will show you the documents you have uploaded only.
Hope this helps,
Thanks for posting, I think I know what is happening!
A PDF file is actually a document file, not an image. It sounds like you have an image in the PDF you want to use or you want to use the PDF as the image. For reference, an image file ends in jpeg, png or gif. Since you've uploaded the document it will be in your Library but can only be inserted into your email as a link. I would suggest clicking the Library tab of your account and finding this file.
If you want to insert a link to the document you can by using the "Insert Document link" option. If you want it to show in the email we will need to convert the file to an image or recreate the PDF as the email.