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I'm trying to create an image in Photoshop CS5, in the image I have smaller images that need to be rotated (25-40 degrees or so), but as soon as I do that they lose quality and you can see zig-zag edges and hard to read text, I made the smaller image into a smart object, but it does not fix the problem, I know it can be done because I've seen rotated screen shots online and they are of good quality, and not vector images either, so what is happening? The image I'm trying to rotate is 1024x768 resized down as a smart object, so the quality to start with is not too great.

PS: The image is of a website screenshot, I'm trying to put it in a portfolio.

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4 Answers 4

The problem is due to the small size of your image.

If you are rotating by an angle other than 90, 180, 270 or 360 any horizontal or vertical lines will come non-vertical, thus giving you aliasing effects. These are also known as "jaggies". It's because a diagonal line has to be represented as a series of steps rather than true angled line.

If you can rotate the higher resolution image and then resize it to the desired size.

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Are you using jpeg? First of all, you should not be using jpeg for screenshots, as it is best used for compressing images with graduated colour, like photographs. Screenshots should be made using .png, or at least .gif.

Also, because of the way jpeg compresses horizontally, when the image is rotated in Photoshop there is a lot of quality loss. This is because Photoshop is not capable of making lossless jpeg rotations.

Jpeg is meant for final output (if suitable), and not for working in.

If you really need to use jpeg, first change them into a lossless format before rotating, and then convert to jpeg again, or use a Photoshop plugin or application that is capable of making lossless jpeg transformations.

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I pasted the screenshot of a website into a PSD file, and I'm working with that, so I'm technically rotating the PSD, I tried saving as PNG but same problem, it's really getting to be an issue, I need to be able to work with these files and edit them so saving as JPEG and rotating after won't work. –  Murtez Sep 15 '10 at 0:39

If you are having this problem with Photoshop, than I guess you are using JPEG.

The article Does Rotating Images Degrade Image Quality? says:

Most images will not lose quality when rotated 90 or 180 degrees. JPEG is the exception because of the way this format is compressed. Some programs can do lossless JPEG rotation, but it is unclear whether Photoshop is one of them.

Initially, I thought that JPEG rotation was lossless when done through Photoshop's File Browser (introduced in Photoshop 6), but after doing some experimenting, I no longer believe that Photoshop can do lossless rotation.

There are quite a few free products that can do lossless JPEG rotation.
For example see JPEG Lossless Rotator.
A whole bunch of such utilities can be found in Lossless jpegtran applications.

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It's not really a deficiency in Photoshop as such, as jpeg is an export format and not a working format. The only real need for jpeg rotation is for digital camera pictures, so programs like ACDSee can do it losslessly. –  paradroid Sep 13 '10 at 6:23
    
As I mentioned in the comment below, I'm working with the PSD of a screen capture, so its not a JPEG yet, it's like any image you need to move around and work with. –  Murtez Sep 15 '10 at 0:40

Is the image you are trying to rotate using indexed color? If so, try converting to RGB color before rotating.

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