tg app modifies the photos on send

guru

When you take a picture with any digital cam, this stores certain information in the JPEG meta data, for example the app of our BQ E4.5:

$ jhead image20181009_001732756.jpg
File name    : image20181009_001732756.jpg
File size    : 2157761 bytes
File date    : 2018:10:09 00:17:33
Camera make  : bq
Camera model : Aquaris E4.5
Date/Time    : 2018:10:09 00:17:33
Resolution   : 4352 x 2448
Flash used   : Yes
Focal length :  3.5mm
Exposure time: 0.060 s  (1/17)
Aperture     : f/2.4
ISO equiv.   : 308
Whitebalance : Auto
Metering Mode: center weight
JPEG Quality : 95

When you now share this photo with the tg app, this information gets stripped away. here for example the result if one stores the sent photo locally again to some place:

$ jhead 246938031_58142.jpeg
File name    : 246938031_58142.jpeg
File size    : 436605 bytes
File date    : 2018:10:09 07:46:20
Resolution   : 2560 x 1440
JPEG Quality : 87

Why is this? A bug?

advocatux

@guru I think it's a privacy feature. All data that is not the basic info (file name, size, date, and resolution) is removed by default.

guru

@advocatux said in tg app modifies the photos on send:

@guru I think it's a privacy feature. All data that is not the basic info (file name, size, date, and resolution) is removed by default.

This is not correct. Even file name, file size and the JPEG Quality are changed, i.e. the file is completely re-written, which explains why the meta data is absent. It does not explain why this is done when I say share photo. I'd expect that the file is shared 1:1.

advocatux

@guru TG uses a different treatment for pictures when you send them "as a picture", and when you do it "as a file"

flohack

"As picture" is being uploaded 1:1 but the server then compresses it. 90% of todays pictures are not worth the high resolution, why I can understand Telegram guys that they want so save space in their cloud. The desktop App makes a difference, but unfortunately on the phone this feature was never implemented. Please file a feature request on the tracker, we might consider it for the new version.

BR

advocatux

@flohack oh! (oops)