Sudden REDUCTION in file size?

[jenniferk44783920]

Duplicated a 200MB file and did some minor changes (additions) AND upsized the file. The copy ended up being 20MB. Only difference is that I have a newer MacBook. And I don't fiddle around with preferences so I can't figure out the massive file size reduction. I only care because my jpg file - for art prints - dropped from 13MB to 600KB and I'm concerned about quality loss.

[D Fosse]

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.

[Bojan Živković]

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.

[Stephen Marsh]

@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