Preview Exporting Huge JPG Files

Hi,

I used to be able to open RAW files from a photoshoot in Preview and then select all the photos and export to JPG with relative ease. I could set the parameters to a JPG export size (usually around 2-3 mb) so I could send to clients for easy viewing.

However, within the past year using the same workflow, now only the 1st 2-3 photos get exported at that size while the rest of the photos export around 131 mb! When I have anywhere from 400-1000 photos to export this takes a tremendous strain on my macbook pro.

The "workaround" was then resizing those large files to about 1000 pixels width but then it saves the files as TIFF which I then have to save as JPG again... however, this task (resizing) usually crashes Preview.

I just would like my Preview to export at the same size the way it used to but I cannot figure out how and have searched the internet with no luck. Anyone might know what I am doing wrong or have a better way (app) I can do this?

Thanks!