Some people often complain that their PC configuration doesn't satisfy Minimum requirements of Photoshop. But its necessary for them. Don't worry, there is a easy solution for you. You can do whatever the Photoshop does without installing any software and in any OS, Its possible only with .

Pixlr is a leading cloud-based set of image tools and utilities, including a number of photo editors, a screen grabber browser extension, and a photo sharing service. It was intended for non-professionals. The suite was acquired on 19 July 2011 by Autodesk. It can be used on PCs, and on smartphones or tablets using an app.
The suite of apps range from simple and playful to advanced photo editing.
If you want to edit a picture, then simple goto, Upload or give a link of the image you want to edit. A page just like Photoshop comes before you. 
It also provides some online tools to add some effects to photos.
They provide a Mobile app "Pixlr Express"  for iOS and Android with More than 600 effects, overlays, and borders to personalize any image, free! Pixlr Express is a fun and free photo editor that lets you quickly crop, re-size, and fix any picture, remove red-eye, and whiten teeth. Hence you can edit pics on the go.
Some Screenshots:
Pixlr Editor Pixlr Editor Pixlr Editor

Android App Store Google Play

iOS app Store