On Mon, 23 Jan 2006 22:04:15 GMT, Commodore Joe Redcloud
wrote:

On Mon, 23 Jan 2006 16:01:19 -0500, JohnH wrote:

On Mon, 23 Jan 2006 20:47:38 GMT, Commodore Joe Redcloud©
wrote:

On Mon, 23 Jan 2006 15:42:28 -0500, JohnH wrote:

On Mon, 23 Jan 2006 15:08:11 GMT, Commodore Joe Redcloud©
wrote:

On Mon, 23 Jan 2006 07:44:01 -0700, "RG" wrote:



I was using some HP photo editing software that came with the camera ...
when you want to downsize a image file it offers two sizes - one
recommended for e-mail and one recommended for images for a web page.
Then, after selecting one of these, it offers a choice of decreasing it by
pixels or by percent of original. This is the part I am not sure about.
I'll try both and see if I can determine the difference, if any.

Shouldn't be any difference. Reducing a 3000X2000 image to a specified
1500X1000 pixels should give the exact same result as a request to reduce
the image by 50%, within the same program. Same resizing and resampling
algorhythms should be used to get there.


More advanced programs such as Photoshop and Paint Shop Pro give you a
choice of several reduction methods and optimizations. I use Irfan
view also, and it does a pretty crude job of resizing, and the
resulting file size is always much larger than those produced by more
sophisticated programs.

Irfanview is mostly useful as a quick viewer when you want to go
through a folder of photos. It's not really intended as an editor.


Commodore Joe Redcloud©

With Irfanview, you can make the file size as small as you want.

You are not understanding the issue. If I take a 1 MB file that is
1200 x 1200 and reduce it to 600x600 in both programs, the resulting
files will be vastly different in size. Irfanview is a handy viewer
and I use it all the time, but it was never intended as an editor, and
that portion of it is very crude.




Commodore Joe Redcloud©

I just resized a 3.74mb (50% reduction) pic in Irfanview with a resulting
filesize of 1.22mb. The same thing in Photoshop Elements resulted in a file
size of 1.629mb. Both were resized at the highest jpg quality.

Something else is going on here besides just the software being used. If I
reduce the dimensions by 50%, I'd expect the file size to be about 25% of
the original. Irfanview is closer to the expectation.

I have never used Photoshop Elements. As I understand it, it is a stripped down
version of Photoshop. My comparison is between Irfanview and Paint Shop Pro, and
the difference is substantial.


Commodore Joe Redcloud

What's strange is that Irfanview is making a larger file than Paintshop
Pro, but a smaller file than Photoshop Elements.

When I did the experiment, I saved both at the highest quality possible. I
don't know what is causing the file size change. But, in my case Irfanview
is making a smaller file, not a larger one.
--
John H

******Have a spectacular day!******