I have a PSD available in portrait orientation but I want it to be resized to landscape mode for creating its PowerPoint templates. I am completely noob to Photoshop, hence can anybody guide me to convert the portrait mode PSD to a landscape PSD without the the images in it getting stretched out?
Resizing image while not constraining proportions will make it look rather squashed, distorted and otherwise not flattering. Why not resize it to fit with some negative space on the sides (or one side), it might even be good to put some text next to it, or even use two portrait-orientated images on the same page if you think looks better... This is not an answer to your question, but it's worth thinking about it...
Or the other solution would be to crop it to fit your dimensions, but you will be losing a large part of your image which is on the other hand questionable on flattering your images... For this, use the crop tool or the Canvas Size operation (Image->Canvas Size).
And another thing, pixelization occurs when you enlarge the with or height (or both) of the image, so you might have a small image, or you need to be reducing the size of your image to achieve what you want...
Have a look at something called seam carving or liquid rescaling. I'm not sure of any implementations, just the theory, but there are some links in the Wikipedia article.
- You could rotate 90°. But that probably wouldn't work for the image.
- You can crop but you will lose a large part of the image that way.
Conceptually, there doesn't seem to be anything else you could do (in any program with any image type) if you don't want 'the images in it getting stretched out.'