Sudden REDUCTION in file size?

@jenniferk44783920 

If you want definitive answers, you will need to provide pertinent information about both files (are you comparing apples to apples).

* Pixel dimensions width/height (i.e. 1920 x 1080 px)

* Colour mode (i.e. RGB)

* Number of alpha channels, if any

* Bit depth per channel (8, 16 or 32 bits per channel)

* File format and settings/options

* Possibly metadata embedded in the file

* Possibly ICC profile embedded in the file

When saving JPEG you always have quality settings. For print or to maintain maximum quality always set to maximum available quality like 12, 10 or 100%. Many will advice you to never use JPEG for print but if you must, try to minimize savings, keep file as PSD untill you are 100% sure thats print version and then save as JPEG with maximum quality.

Jpeg uses very aggressive data compression to reduce storage size. The jpeg algorithm can reduce file size down to 2-5% of the native full size.

But there's a price. Jpeg compression is always destructive, non-reversible and cumulative. Saving to jpeg will always degrade the file slightly, no exception. Every resave to jpeg degrades the file further.

If quality is the main concern, don't use jpeg at all. Use TIFF, or for web images, PNG.