Responsive View
Test your responsive design across different devices
15 Alternatives To Responsive View
2015 Design Tools
Results from survey of 4,000+ designers on their fave tools.
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Design Principles
An open source repository of design principles and methods
Landscape by Sprout Social
An interactive tool for social media image resizing
Placid
Generate og:images and twitter:images automatically
Rapid Responsive Design
Kill your artboards, design for all sizes faster
Salieo
Intelligently responsive images.
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Squash 2 for Mac
The easiest way to compress and optimize images for the web