does Dropbox compressed photo files???

@Ira  I don't know how I could make it any more clear from my example above that the photo was unchanged. The byte size is EXACTLY the same as is the RESOLUTION of the picture.

As with your mention of md5 checksums - yes the checksum will be different because dropbox adds one extra EXIF in the file, which will alter the md5 checksum. They also apply the Lepton compression while storing jpgs on their server. They just decompress them back when you grab them.

This is the same as you placing all your jpgs into a compressed zip/rar file and then decompressing them when you need them. It's the SAME EXACT photos. I don't see what the problem is here. 

My 5cts: I found out today that I experienced the same problem with Android Camera Upload (files from 2015).

Photos uploaded through the Camera Upload feature differ from manually copied files. Not all of them, but SOME. Note: desktop-dropbox does not have this problem.

I would like to add that this is not purely filesize and EXIF. The pixels of the image definitely change. Here's a comparison of the two files in Tim's Github:

https://www.dropbox.com/s/z7nujvdq5nfk3kg/AFC_JPG_and_Dropbox_jpg.png?dl=0 (look at the top-left, for instance)

Does it make a visual difference? No.

But do I like Dropbox making this decision for me? Also no...

I would like to know exactly what is going on here.

I sent some files to a client by sharing it inside a shared folder. The file was 262 kb. When she downloaded it, the size was 226kb. We cannot figure out how to keep the files from compressing.

WhiteRobin - If you don't want the file to be altered, I think you may have to put the images inside a zip file. That way, Dropbox will not perform any post-processing of the images.

This is bull**bleep**. I just signed up for Dropbox and I'm glad I only paid for the first month. I just uploaded my image files in .png format and they are 65mb each. I sent out the link to all the university students so they could all have high quality copies.

When I download one of those 65mb images to my desktop, it was 1.7mb.

**bleep**, and hundreds of people got that link and will see **bleep** images after all the work I did.

WTF Dropbox. I'm quiting after this month.

I see someone from Dropbox says everything is EXACTLY  the same and uncompressed.

**bleep** **bleep** **bleep**.

Lol comment of the year!

I use Dropbox to save resized images to be used in social media, for example a tif to a 1024 x 1024 jpg at 100%. I’ve noticed that this size is now 800 x 800 and I’ve begun to see halo effects. I don’t see these in the original nor in the jpg if I save to my hard drive. I then export the photo to my Photos and the halo is still there. It looks like Dropbox is using the 800 x 800 image to export to IPhotos, not the original file. This is going to be a problem and will have to use another service.

BTW, I am exporting rthe jpgs from Lightroom.

One thing I haven't tried yet is saving the jpg to my hardrive and then copying it to Dropbox.