Personally, when I need a small JPEG from either Id, I generally export as a PDF(Print) with all compression set to None. I then open the PDF in Ps and use its "Save for Web & Devices..." to generate a small JPEG for email, web, or whatever the need. I like managing the resampling and compression in Ps.
The final results can be better exporting from Id as a JPEG, with the format's lossy compression, and then resampling the JPEG in another program.