Size Of Cover Art File is incorrect

as of today the file size of the cover art picture is no more the same in MP3Tag and the Windows explorer. The MP3Tag coversize is bigger than the windows explorer shows. What happened?
Example: in Windows explorer the file size is 89 KB and in MP3Tag this is shown as 105 KB.

Could you supply such a picture?
I just checked in 3 folders with different pictures and the only difference in size I found with one shown as 36KB in MP3tag and 36.9 in the explorer.

I am not so sure about where and how you compare the sizes:
Is that an external file vs. an embedded one?
Or are these always external files?

indeed I compare an external file with an embedded one. Up to today this was almost identical. But here is an example where this is not the case.
Screenshot Explorer

Do you see the difference?

What does the size look like if you export the embedded cover?
(I did that for the 3 folders and ended up with the slight difference of 0.1KB for just 1 of the 3 pictures)

This would be the one:

I have extracted the cover from MP3Tag into a file and it ends up with 64KB in the explorer. If I do cut and paste from MP3Tag into and try to save with 100% size which should end up with identical size -- I get a file of 128 KB !! This is weird for me.

Copying and pasting via the clipboard may lead to an intermediate format which is not the original.
So if there are further processing steps involved, it is a little tricky to attribute the final result only to MP3tag.
To extract the cover from MP3tag,

  • select a single file
  • navigate in the tag panel until you see the cover section.
  • right-click on the cover picture and select
  • "Extract cover ..."
  • set a filename that you can recognize and remember the path
  • compare the exported cover and the embedded data
    What does that show?

That is what I described before: I have extracted the cover from MP3Tag into a file and it ends up with 64KB in the explorer

As I cannot reproduce it - could you supply a source file so that I can extract the embedded picture and see why I do not see such differences until now?

Best Of The Beast

I had more the audio file in mind. Sorry for being too vague.

If I save that picture from your post, I get a file with the size of 75KB ... so that does not quite match your figures.
That is why I ask for the audio file.

The following File has 88 KB in the Explorer, 97 KB in MP3Tag
D Generation No Lunch

I just took the Iron Maiden picture file from the post (75KB)
Embedded it in a file
Extracted it to the file "iron maiden.jpg"
Here is the result:

all of them have 75KB ...
So what about the audio file? As apparently exchanging pictures does not really lead to a solution.

Edit: downloading the DGeneration picture leads to a file with the size of 77KB ... only the pictures do not seem to do the trick.

Mmh, the Iron Maiden jpg on my PC shows 83 KB in the Windows explorer, which translates into


So where is the difference between your PC and mine when the same jpg is not the same size on your PC? Any clou?

As you were asking about the audio files: all are MP3 with 320kbps

I bet that the upload does some kind of transformation. That is why I think that the original audio file is better for testing.
Still, if we both follow the same procedure (like I described in

then the principle result should be the same.

The origin of this thread is that apparently in your environment differences occur that so far I could no reproduce.
We have exchanged the description of procedures, the pictures - now the only variable would be the audio file.
And if all these tests still show no reproduceable results then you would have to find out locally what lead to your observation.
Without reproduceability it would virtually impossible to get rid of the alleged bug.

Is there any chance you have different tag versions for these mp3 files, APE and id3? I can't tell from any of your screenshot images. Try looking at the Extended Tags panel and see if you have more than one type stored.

And now the correponding audio file so that others can extract the cover ...

In my opinion file size is not a good way to compare image quality. That's because image files often contain a variety of other information (for example tags like "Exposure" or "Date Taken) that are not part of the image itself. And when an image is embedded, extracted, or pasted it may add or exclude some of this info, causing a change in the file size.

A quick and easy way to compare image quality is to use the Media Info utility (MediaInfo - Download). In Windows Explorer right click on an image file and choose Media Info to show its basic characteristics, highlighted in the red box below:


If those seven characteristics match, then any file size difference is irrelevant.