How to resize image?

How do you usually resize image yet still maintain the quality ?
For example: a 200*200 image become 1500*1500.
Is this feasible ?
Thank you

I've never been able to go from small to large with any quality. I came to the conclusion it's not possible, but I'd be just as curious if there is a method I'd like to know it too.

I dont know of a way to go from something that small to something that large without a major loss of quality. You can probably go from 200 to 300 or 400 with out too much loss of quality by using the crop tool and setting it to the size you want, and then applying a unsharpen mask and adjusting the settings. but to get it that big you would lose alot of quality.

Like the workspace that i post at the hardware forum, it was taken by myself using my digicam. But the quality is very poor. Like this http://www.freebiesresources.com

How to make photo quality better ?

I copied the picture and tried everything i know, and i could barely get any better quality out of it. As soon as i fixed one thing, it made another worse.

I very much doubt this is possible. When you think about what makes a picture viewable in good quality on computers etc etc is the pixels. By increasing the size of an image, you are really streching the pixels. You cannot add other pixels to an image to make the quality the same or similar.

Thats the way i see it. Most likely wrong.

can it be done by increasing the DPI ?

I wouldn't bother with the DPI. The resampling of raster images in Photoshop is decent.

In Photoshop, right-click on the image's title bar or go to "Image" in the text menu and choose "Image Size...", then reset your pixel dimension where you want them.

200px to 1500px is pretty huge. My preference would be to locate a higher-res version of that image, or just find a better image all together.

Will lose quality when you size up a raster image, but you can work with some of the sharpening filters to try and clean it up

DPI is irrelevant. DPI is purely for printing, and really has nothing to do with screen resolution.

Increasing the DPI only means that it'll put more pixels in a given space in PRINT.

a 100x100 image at 100 DPI will print 1"x1" square.
a 100x100 image at 300 DPI will print 1/3"x1/3" square.

Both images will still be 100x100 pixels and appear the same size on-screen.

You CAN interpolate images to be larger than the original, however there's a limit. You may be able to go up to 400% bigger (turning say a 100x100 image into a 400x400 image), before you start getting really critical image loss problems.

When you resize, in Photoshop CS, choose "Bicubic Smoother" as the resampling mode, or get some pro interpolation software like Genuine Fractals Pro.

Going from 200x200 to 1500x1500 is going to pretty much be an impossibility if you want to keep quality.

ok .. thanks guys

Hi!

To enlarge an image you have to add pixels to the original image.
This is accomplished by using interpolation algorithms.
Some algorithms are better and can produce good results.
I use PhotoResampling software that allowes you to choose between many algoritmhs. To upsize photo GBLS is the best. Have a look at: http://www.photoresampling.com.
You can download a free demo version.

Hey guys,

As a side-note, if you are blowing up (resampling) a screen image in Photoshop, you can use the "Nearest Neighbour" re-sample mode (available in the "Image Size" dialog) which will effectively increase the size of the pixels in the image (so you end up with an image which still looks like it's made up of pixels).

If you choose one of the other modes (bi-cubic or bilinear) it will make the new image look fuzzier.

Depends on the effect you're after. But if you want to change a tiny pixel-based image to a really large one, "nearest neighbour" is the way to go.

Cheers,
Dave

I want to explane a little about resampling. The davenewt method (Nearest Neighbour) is the worst algorithm that you can use. No any product , except PS, offers this algorithm. It's based on pixel replication. So in enlarging an image you get large pixelate areas. Of course the effect is more and more visible as the upsizing increases. That is the resason many people worked and still work to find better algorithm.
If you think my explanation is poor, ask me or surf in the web!

Yes, it sucks for most things - but not for upping pixelated images that you want to remain pixellated

Cheers,
Dave

i think the best advice is try to get it rite first time, and it also depends on wot software ure atually using, a size of a image is relly important