"Save" or "Save as" function greatly reduce the size of a picture

[malletp]

Version XnView MP (1.4.4)

Hello,

Description of the different cases :
Picture from my smartphone : toto.jpg -> 4032x2668 -> 3,01Mo

• I open toto.jpg and I do a "fake crop" with an area that is 100% of the picture. "Save as" toto - croped.jpg 4032x2668 -> 1,43Mo (?)

• I open toto.jpg and just do "Save as" (no crop) : toto-2.jpg 4032x2668 -> 1,43Mo (?)

• in thumbnail view, I copy toto.jpg to toto-3.jpg -> 4032x2668 -> 3,01Mo (OK).

• I open toto-3.Jpg and just do "Save" : toto-3.jpg 4032x2668 -> 1,43Mo (?)

=> Is it normal that "Save" or "Save as" functions reduce pictures size by 2 without having performed any modification ?

Whaat is the difference between toto.jpg and toto-2.jpg ? (I guess some informations are missing)

[xnview]

What do you have in Settings>Write>JPEG?

[malletp]

Hello

What is od ?

In settings/Formats/Write/jpg I have:

Quality : 80
DCT Method : slow
smoothing factor : 0
Subscampling factor : 2x2, 1x1, 1x1 (default)
Rebuild embedded exif thumbnail : true

Keep exif : true
Keep IPTC : true
Keep XMP : true
Keep ICC profile : true

[xnview]

perhaps your original picture file is saved with 100 quality