Compact old files

  • Thread starter Thread starter shakey
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shakey

I hesitate to do this unless I can exclude JPG files as surely they would
lose some quality. Is there a way to exclude them from compacting?
SG
 
shakey said:
I hesitate to do this unless I can exclude JPG files as surely they would
lose some quality. Is there a way to exclude them from compacting?
Click to expand...

Compacting files using ZIP or similar technologies is lossless: files
lose nothing; the quality of images is unaffected.
 
shakey said:
I hesitate to do this unless I can exclude JPG files as surely they would
lose some quality. Is there a way to exclude them from compacting?
SG
Click to expand...
JPGs are already compacted, and there is little likelihood that XP's program
could compact them more.
Jim
 
Jim said:
JPGs are already compacted, and there is little likelihood that XP's program
could compact them more.
Jim
Click to expand...

Correct. jpg's are not harmed in any way by compression programs like
WinZip and the like, but they also compress no more than 1-2% at most.
As Jim wrote: They're *already* compressed - it's the nature of the format.

Tony
 
Tony said:
Correct. jpg's are not harmed in any way by compression programs like
WinZip and the like, but they also compress no more than 1-2% at most.
As Jim wrote: They're *already* compressed - it's the nature of the
format.

Tony
Click to expand...

Nonsense, you can easily compress a JPG by an amount much greater than 1% or
2%, (and often w/o too noticeable results).
 
Bill in Co. said:
Nonsense, you can easily compress a JPG by an amount much greater than 1%
or 2%, (and often w/o too noticeable results).
Click to expand...
Of course 1 or 2 % would not be noticeable either in the quality of the
image or its size.
To really make much of a difference would take serious compaction, like say
50%.
How much compaction the OS functions could do, in addition, depends on the
amount of
compaction that the photo editing program did. It isn't easy to determine
the amount of
compression because different programs report it in different terms.
Jim
 
Bill said:
Nonsense, you can easily compress a JPG by an amount much greater than 1% or
2%, (and often w/o too noticeable results).
Click to expand...

Tony was referring to non-lossy compression. I trust you know the
difference, as your comment in this regard appears misleading.
 
C said:
Tony was referring to non-lossy compression. I trust you know the
difference, as your comment in this regard appears misleading.
Click to expand...

I thought the talk here was of 1 or 2% compression (which is no value
whatsoever).
And if we're talking about how much Winzip would compress included JPGs, my
guess is it would be a whole lot more than that.

And finally, with JPGs, it's easy to compress by a whole lot more than that
w/o much noticeable effect, so I thought it was misleading.
 
Bill said:
I thought the talk here was of 1 or 2% compression (which is no value
whatsoever).
And if we're talking about how much Winzip would compress included JPGs, my
guess is it would be a whole lot more than that.

And finally, with JPGs, it's easy to compress by a whole lot more than that
w/o much noticeable effect, so I thought it was misleading.
Click to expand...

You must be referring to a process that I admit I am not familiar with.
I have many zips of vacation pictures that I store by year/location in
WinZip archives. I have never gotten more than 1-2% compression. If I
put 10 MB of pics in that archive, the compressed size will be about 9.8 MB.

Tony
 
Tony said:
You must be referring to a process that I admit I am not familiar with.
I have many zips of vacation pictures that I store by year/location in
WinZip archives. I have never gotten more than 1-2% compression. If I
put 10 MB of pics in that archive, the compressed size will be about 9.8
MB.

Tony
Click to expand...

I have seen zips compress some types of files by a pretty significant
amount, but I can't recall which ones specifically (although I'd expect Word
documents or such would get the most, and exe files, the least). But if
you have done the tests with JPGs, and consistently only get 1-2%, than you
know for sure (I don't).
 
I have seen zips compress some types of files by a pretty significant
amount, but I can't recall which ones specifically (although I'd expect Word
documents or such would get the most, and exe files, the least). But if
you have done the tests with JPGs, and consistently only get 1-2%, than you
know for sure (I don't).
Click to expand...

Ah, so. I thought all we were talking about were jpg's. Any text
base file, yes - 50% or more reduction in size is common.

Tony
 
Tony said:
Ah, so. I thought all we were talking about were jpg's. Any text
base file, yes - 50% or more reduction in size is common.

Tony
Click to expand...

I was just surprised that JPGs, when zipped, were only able to be compressed
by 1-2 %, from what you've said. Perhaps it's not all that surprising,
though. (EXE's, I can see, however :-)
 
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