Why does saving an image without changing anything in Paint reduce size drastically?

[Black Panther]

Take this picture here:

I opened it with Paint, then selected "Save As"

and voila from 3.2MB this file went down to less than 600KB while keeping it same format (jpg) and not editing anything

What's the deal here?

 

[cheesy999]

Paint saves in a higher compression ratio

 

[newtekie1]

Paint saves in a higher compression ratio

And as such a lower quality. It might not be noticeable to the naked eye though.

 

[cheesy999]

It really depends on the size of the picture on the moniter/how much your zoomed in as well as the complexity of what your photographing

 

[KieX]

Try Paint.net, lets you adjust the file size /quality. Pretty much replaces stock paint imho

 

[95Viper]

Try Paint.net, lets you adjust the file size /quality. Pretty much replaces stock paint imho

+1 on that, and it is free with no nags or anything.
I, myself, have donated to them, as, I use it regularly.
They, even, have an on-line community, tutorials and you can use plug-ins.
It makes use of layers, optimized for multicore and multiprocessor, special effects, auto updates(if you want it to), and a boat load more.

Paint.NET v3.5.8

 

[FordGT90Concept]

If memory serves JPEG has 10 quality levels from 1 to 10, 10 being the highest quality. The image may have been originally created with a setting of 10 and Paint probably does ~5. This is why saving the exact same image with Paint, the size is drastically reduced.

If you don't want Paint to reduce the quality, save as bitmap or portable network graphic.

 

[Drone]

Well ... it's a rule of thumb: if image/video/audio file size decreases you lose data quality. If you take a photo saved directly from a RAW photo and save it as JPG you will lose in quality. If you will save that JPG over and over it will get worse. Each and every save will just add random noise evenly spread throughout the original image.

Btw this is a good site: http://errorlevelanalysis.com/

You can check image error level there.

 

[MilkyWay]

+1 for Paint.net its basically what i use. Gimp for Linux, Paint.net for Windows.

 

[RejZoR]

I'm using Paint.NET for ages. A brilliant little thingie. Photoshop Lite if you want it that way.
It's free but still powerful enough that i never ever think of Photoshop for my needs.

 

[Funtoss]

Lol, i always wondered as well :L

 

[FordGT90Concept]

Well ... it's a rule of thumb: if image/video/audio file size decreases you lose data quality.

Not necessarily. Saving a bitmap as a PNG will substantially reduce the side of the file but the quality is exactly the same.

BMP is lossless and uncompressed.
PNG is lossless and compressed
JPG is lossy.

 

[Bundy]

.jpg is a compression format (i.e. lossy) so it will always be smaller. If you want to save the quality of a picture, you should select .bmp.

i.e. if you are doing lots of editing/saving/editing/savings etc - use .bmp and then when you are finished, save as .jpg - don't use .jpg as an editing format

 

[Drone]

Not necessarily. Saving a bitmap as a PNG will substantially reduce the side of the file but the quality is exactly the same.

BMP is lossless and uncompressed.
PNG is lossless and compressed
JPG is lossy.

Png is not lossless. My trained eyes can spot the difference.

 

[RejZoR]

PNG is lossless unless you're using some crappy encoder that does it in a lossy way.

 

[FordGT90Concept]

I doubt a crappy encoder exists. PNG is all standardized. The images (any image -> PNG) are 1:1 identical except in binary. PNG is lossless and always has been.

 

[Steevo]

How many ways to screw in a lightbulb.

http://www.techpowerup.com/forums/showthread.php?t=134578


Instead of each pixel being mapped and having a location and color value assigned, areas of like enough color are mapped and given color values.

 

[FordGT90Concept]

Yup, which is why PNG is excellent for images with large areas of solid color.

 

[Sir B. Fannybottom]

It's because a raw image has ROM files which have coulor settings and such, when you put it in paint it deletes it and them compresses some part of the image

 

[LAN_deRf_HA]

I know for photoshop at least jpg has 12 levels. I usually go with 10. I switched to either saving everything in png or pasting screenshots into photoshop instead of paint as the compression in paint just ruins game screenshots. Like why even bother saving with how crappy it looks... unfortunately it took me awhile to pay enough attention to notice the dithering and what not so I have all these shitty quality old screenshots. Now though I just use fraps with png.

 

[Drone]

I doubt a crappy encoder exists. PNG is all standardized. The images (any image -> PNG) are 1:1 identical except in binary. PNG is lossless and always has been.

The official png website states that png is inherently lossless

filters can be added to it to make it lossy and hence provide greater compression

http://www.libpng.org/pub/png/pngintro.html



And btw if you have no idea JPEG 2000 and JPEG 1992 are truly lossless

http://www.jpeg.org/jpeg2000/

 

[Squeezemaster]

Someone recently suggested that I use MS Paint in my Win 7 machine to reduce file size without reducing image size. I gave it a try. I opened a 137mb tif file that was exported from LR 5 with the Prophoto RGB color profile into MS Paint and immediately saved it as a tif without changing anything to the file. The resulting tif file was only 14.8 mb! The image size was identical to the 137 mb file. Paint did not change the color profile. I opened both files in PS CS6 side by side, extremely zoomed in on areas of the image and could not tell the difference by looking at them on the monitor. There was no banding as usually seen in compressed jpgs. No apparent loss of detail at all. I have been looking online for an explanation for HOW Paint does this and found this relatively old thread. No real answers to be found here but at least the topic is addressed. I can understand compressing a jpg to reduce file size, but not a tif file. My plan is to make extreme crops from both files and have them printed to see what I get. This should be the real test for the MS Paint file size reduction. BTW, I have over 35 years of professional photography experience and look at images very critically.