You can clearly see the difference in the very bright colors, not the darker or background colors.
 
The top screen cap with Applejack, look at Timber Spruce’s hair at the tint and his red shorts. It’s clearly desaturated and darkened. The one in the Description is better. Look at the contrasts on Pinkie and Sunset. The proper version, Pinkie has a brighter pink, while the desaturated version has a grey film to it. Sunsets hair is the same way.
 
MLP’s color palette was never meant to be this muted and shows you have an inferior version\format.

Screenshots are uploaded from whatever source people are watching, and there should be no surprise that many people are watching the officially released English YouTube versions. YouTube is extremely popular, after all.
 
It’s true that on a calibrated screen there is a definite difference between the versions, but unlike some people I don’t have a problem with people uploading either version. At least they aren’t suffering from severe compression artifacts or incorrect aspect ratios.

@Spike_Lover  
I think the increasingly short period of time between Acceptable screenshots and Actually Good screenshots these days probably has a lot to do with that. It’s still something that really should be handled by just uploading a new image and reporting the old one.

@Spike_Lover  
And these are practically indistinguishable.

@TexasUberAlles  
I remember people never got upset before when desaturated screenshots of the show or eqg were uploaded

@Spike_Lover  
It happens. New uploads of screencaps once better sources become available has been A Thing all along; it’s still worth uploading the early releases so people can see them until better ones come out.

ಥ_ಥ  
_{Im the one who uploaded the one the right}

If you click on the [Reporting] tab under the tags, one of the options is [► Updated or previously uploaded]; go to the inferior version, click on that, enter the page number of the superior upload, and add “better quality upload” in the [Explanation] box.

Because of reasons.

Y’know, its possible its not a choice on the upload, but simply something that happens to the videos when uploaded to youtube? Part of the processing, maybe.

I can hardly see a difference.

@ponysopher
 
The one on the right is more muted, but looking at 2 different monitors shows me the difference is incredibly minute. It ain’t as bad as Mirror Magic.

It’s more the resolution… sheesh… maybe HiDPI thumbnails aren’t enabled or something…
 
 
Yup… that looks like 150 x 150…. HiDPI thumbnails do 600 x 600… that’s definitely not 600 x 600…

@LanceOmikron  
The colors are clearly muted in a couple of the images. If you can’t tell, get a new monitor.

Even looking carefully, I can’t tell the difference.

Why does it look like an ad that would give me a virus if I click it?

Gah… it’s like when people take low-quality screenshots off Youtube days or even weeks after it aired and I’m just like why didn’t you just download off of yayponies… gah

@leash  
This

youtube is easier for people to access because people like free stuff