image resizing without losing quality

It is depend on what kind of image you are resize.
Is it GIF or JPG, error diffusion, no dither or ordered.
if the error diffusion and 8 bit, then no way to resize it lossless, and is the worst type if you resize.

If you resize the 24 bit image, but don't resize it too much, then there must be no problem.

5.5 does the same as 4.0.

if you resize an image and it is not too lose its quality, then you can add small amount of blur to cover it, and of course your image will blur.

You simply cannot resize up without loosing quality. Its purely a matter of how many pixels youve got and how many you want and no matter what you do you cant magically create more pixels that you dont already have. However there is a utility that can cut down on the ammount of loss and do it better than photoshop can. Its called Genuine Fractals and it resizes by translating your image into a complex mathematical equation or a fractal sort of thing. It can then size up to about %400 without MUCH loss. You will still see some loss but its not nearly as bad as photoshops at %400. GF is made by altamiragroup and they can be found at www.altamiragroup.com.

Exactly, there's no way to resize the image without any losing its quality.

You can have a resized image which have only little losing quality: don't too much enlarge the image (don't enlarge the image over 200%)

If your image is a GIF that using error diffusion method of it's dithering, then it almost impossible to have an enlarge image that didn't losing its quality.
Error diffusion is good when it on the original size, but not when enlarge it.

if you still want to enlarge it, to reduce the noise that happened, try to use the Noise -> Despeckle or Noise -> Median (try both of the filter to get the maximum result)

5.5 just did the same as 4.0
because not the software's ability, but the quality and compression method of the image.

Sorry, double comment message

um fozy...didnt i just say that? Go back and read my comment. You said exactly what i said.

Um... to get the best possible quality when resizing, make sure you are in RGB color mode (or cmyk) and NOT indexed.

This is as good as you can get.

There is a techique known as resampling, it can be used in applications like Paint Shop Pro... but I don't think Photoshop does it.

Not much improvement anyway.

Any program that resizes up will "resample" including photoshop. You have 3 choics for resampling as well in the Image Size dialog (in photoshop). Make sure youre on Bicubic and not the others. However this is what weve been discussing, resampling will KILL your quality. Which is why I suggested Genuine Fractals which uses a different method.

Weed,

well, Paint Shop must use a different resampling alorythm that Photoshop because the results a very different... not better, but different.

Very possible. There are many many different ways to resample, bucubic currently being the best aside from Genuine Fractals method which may or may not qualify as resampling.

I would have replied excellent-but the question was already answered previously in the comment. That is just a good example of "image manipulation"--everything has already happened, we are just merely copying and Manipulating it. But anyway I would THANK EVERYONE who participated and helped me with my question. I tried and am using Geniune Fractals and its doing its job pretty good.--THANX!!