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Is there any way to losslessly export from Picasa? Even when there are no edits there are differences in exported files vs the original - when exported with automatic (ie, original) quality and original resolution.

$ diff 1-IMG_0412.JPG IMG_0412.JPG
Binary files 1-IMG_0412.JPG and IMG_0412.JPG differ

Manual copying is tiresome and defeats the purpose of using Picasa in the first place. If lossless export from Picasa isn't possible, any suggestions for a fast photo manager in Windows that doesn't do shady stuff like this?

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2  
Are you sure that the actual image data is resaved in this case? It may simply be that metadata has changed, causing the binary to differ. –  mattdm Mar 31 at 14:15
    
With Jpegs Picasa stores metadata in the files itself so this is likely. –  his Mar 31 at 16:13
2  
To verify this, if you are on Linux you can use 'jpegtran -copy none -outfile out.jpg in.jpg' to remove all metadata (otherwise lossless). Diff the files again and see what comes up. –  mivilar Mar 31 at 17:49

1 Answer 1

up vote 0 down vote accepted

In practice, it isn't really possible to use Picassa's "Export to Folder" losslessly.

This is because in fact the file isn't copied/moved but loaded and re-encoded with God-knows-what settings, besides of that 'Automatic - preserves original image quality'.

JPEG writing engine has much more settings than 'Quality': DCT method, Subsampling, Smoothing etc. See for yourself bellow:

JPEG engine

I searched enough time for the the program with the best (biggest number of actions/options/transformations) and fastest (yes, I did many benchmarks - I was forced to) Batch Processing engine as well as with the most flexible on-disk primitives (Copy/Move/Rename for many files selected on different criteria) and for me this is XnView MP (new version with many improvements and bugfixes is due soon).

It supports multi-selection, searching, filtering etc.

You can download it, is freeware. Of course YMMV.

Disclaimer: I'm not the developer of program, just an old user. Also, beware: the program is quite deep - there are forums to ask.

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