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Participant
October 14, 2023
Question

Files upsizing upon export from Photoshop

  • October 14, 2023
  • 1 reply
  • 176 views

I've been having problems with downsizing an image size in photoshop (in this case I want photos to be 3mgs. or slightly less) and upon export they upsize. The example: I downsize a raw file (22 mgs) to 3mgs. in Photoshop. When exported the file size in the finder is 5.2. This happened with 3 out of 5 files exported. All images were shot at the same time, with the same settings. I just spent two hours on Zoom with a photoshop expert who couldn't figure it out either. Has anyone else experienced this? Thanks.

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1 reply

D Fosse
Community Expert
Community Expert
October 14, 2023

File size is the product of several independent factors:

  • pixel dimensions.
  • number of channels. A raw file is a single channel, but an RGB file is three channels, so three times bigger.
  • data compression. Jpeg is extremely compressed, reducing a file to anywhere between 1-5 % of full native size. PNG compression is less effective, but not destructive
  • image content! The jpeg compression algorithm works much more effectively on flat areas than on busy detail, by a factor of up to 10 x.

In short - the file size indicates precisely nothing.

Participant
October 14, 2023

Thanks, but then what is the best way to try and reduce a raw image down to a 3mg. file size. I'm stumped.

D Fosse
Community Expert
Community Expert
October 14, 2023

Either crank up the jpeg compression - in other words, go down in quality level - or reduce the pixel size.