Hi Merlin,
Here is a quote from the Lawnsite FAQ. Maybe it will help you post your image.
"To attach a file to a new post, simply click the [Browse] button at the bottom of the post composition page, and locate the file that you want to attach from your local hard drive.
Only certain types of files may be attached: these are the valid file extensions for files to be attached to this board: htm html gif jpg jpeg png txt zip bmp jpeg doc xls pdf.
After posting, the attachment will show up in the body of your message. To view the contents of the attachment (if it is not already displayed) simply click the filename link that appears next to the attachment icon .
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