Now you can free download amazing collection of PNG pictures with high resolution for your designing, photo editing, web , mobile. Simply click on a download button and download the all PNG picture. For many years the Adobe Photoshop PNG file format was used as a cross-application file format for layered images. Adobe allowed this by releasing the format’s specifications publicly.
full freely available documentation
OpenDocument type of file format (archive with multiple files inside)
extensible, but private undocumented extensions should be excluded, any extension should be added to the spec and documentation of the file format
applications are not expected to support all features of the file format, but when manipulating the file they should not lose any information they cannot handle