This little PNG editing Encyclopedia will address all your PNG / transparent background photo editing problems. Some of the tips, tricks and tools are for advanced users who know some degree of photo editing like photoshop or similar tools. Most of them are for regular non technical users without any knowledge of photo editing.
Free online PNG Editors
1. Pixlr PNG Image editing tool
This is a very useful tool with a free option. You need to sign up to be able to use the advanced features. There are both starter and advanced features. If you know how to work with layers, like you do in Photoshop it will be a piece of cake for you. There are also quick-fixes for common problems in regular photos. You may create new PNG photos from scratch. Use this tool for artwork, textual graphics and image editing.
2. LunaPic online transparent PNG editor and GIF maker
This is a much simpler tool for newbies and naive users. There are many common editing features like paint bucket, Text addition, brushes, pencil, cropping, resizing etc. You can also use borders, presets, filters, and some very kool (though classic) animations. You can directly load a picture form your computer of provide an URL from the web and start editing.
Desktop PNG Editing applications / software.
1. Photoshop – World’s No1 image editor.
Photoshop is a feature pack professional software for advanced image editing and graphics creation. You will find thousands of tutorials in articles and videos describing how to use a particular Photoshop feature to edit PNGs. Here is my little tutorial showing you how to edit PNGs that are locked in Photoshop. This is a paid product, though free trial packs are available.