Why file size increases after Save

[kaliona]

Paint Newbie here. Great product, and I'm glad I stumbled across it.

I used Paint to edit a .tif image that was originally about 300 KB in size. All I did was erase a few objects. When I saved the file, the file size jumped from 300 KB up to 2048 KB!!! Can someone tell my why? And is there a setting to keep it from doing that?

Thanks

[barkbark00]

What file format did you save as? Did you add any layers?

[kaliona]

I didn't add anything to the image. All I did was use the eraser and erased a few pixels. Then I just clicked on "File", and then "Save". The image was saved as a TIF, just like the original, but increased in size as I described in my first post.

I also tried this: I opened a TIF image, did NOTHING to it, and saved it. The same thing happened...the file size increased from 300 KB to 2048 KB.

I'm confused.

[Mr Frojo]

Yea, this happens to me when I touch up pictures. I make a few changes to the picture, save it as the same format, and the file size is increased by a lot.

[usedHONDA]

Well unless you absolutely need to use a TIFF, I recommend you save it as a PNG. It's basically the same thing, but PNGs are smaller files.

[kaliona]

Saving as a PNG also would work for me. Yes it is a little smaller than saving as a TIF but the PNG format is still 5 times larger than the original as opposed to 6 times larger when saved as a TIF. I'm still looking for the cause. The resolution doesn't appear to be changing.

I just tried the same thing with Microsoft Paint and when I saved the file as the same format (TIF), it went from 314 KB to 478 KB. Now I can live with that small increase.

[david.atwell]

With a file size that small (I assume that "KB" isn't a typo, and it's not actually "MB"), the size difference could probably be explained with the addition of metadata.

[Mr Frojo]

My pictures went from 2-3mb to 4-5mb.

[kaliona]

The file definitely goes from 313 KB to 2,048 KB. No typo. I don't know exactly what metadata is, but that much of an increase after doing nothing but opening the file and immediately saving it can't possibly be caused by additional metadata.

[Myrddin]

I've known one of my .tif files to start a 1.3 MB and resave at >6 MB.

I do believe that david is right in what he says, that it's metadata (pieces of information about the file embedded) that is the cause of the increased file size. From what I've heard .tif files use a sort of tagging system to mark the data and how it arranges the pixels somewhat differently to .jpeg or .png. As a solution I would do as usedHONDA suggested and save as a .png, then use a PNG compressor such as PNGGauntlet to shrink the file size dramatically.

[Rick Brewster]

This is probably because you opened a low-bit-per-pixel TIF (say, 1- or 4-bit). Paint.NET works with and saves everything at 32-bits.

[david.atwell]

The file definitely goes from 313 KB to 2,048 KB. No typo. I don't know exactly what metadata is, but that much of an increase after doing nothing but opening the file and immediately saving it can't possibly be caused by additional metadata.

Yes, it can, actually. Although Rick's post sort of explains everything...

Metadata is information about the file in question that is stored within the file itself: or, more simply, it is data about the data it's in.

For example, this sentence has metadata because it refers to itself.

In computing, the data can refer to anything in the file about authorship, dates, sizes, number of times opened...basically, anything that would ordinarily appear in the "Properties" dialog when opened, stuff used by the computer to explain how to open it, what program to be used, any number of things. Opening it in PdN would probably populate a whole lot of previously blank fields, and on an image that tiny, it could easily balloon the size. Image sizes in the KB range are subject to vast fluctuation simply because, these days, that's really, really small.

But, as Rick has explained, that's probably not what's happening here. I just wanted to clarify.

[kaliona]

Thanks for the explanations David and Rick. Makes sense to me now. Thanks for your suggestion too Myrddin, I might try a PNG compressor to keep the file size down.

Great program, great forum!