I need to export a few images to a designer to get a promotional card designed.
I exported using the DNG setting, losslessly compressed.
Why would you send them DNG files? Do you know which RAW converter (if any) they will use? Do you know exactly how the colours/etc will turn out in their software? Not every DNG-capable software will recognise the current version of the LR/ACR adjustment instructions.
You should be using something like TIFF for this. I regard DNG as more of an archival format than a delivery format.
Now, on the e-mail, there is a jpeg displayed of the exported DNG image.
All the adjustements are gone. I only see the raw image as shot in the JPEG display (which comes with the dng, when you export to dng).
Does that mean the exported image also has lost all its adjustments?
I have exported in JPEG before, and in PSD, all went fine.
Nope. It just means that the preview JPEG embedded into the DNG has not been rebuilt by LR, and is derived from the underlying image. This is (unfortunately) the normal behaviour. But the DNG file will still contain your adjustments.
However, I strongly doubt that you really want to be sending them DNG files!