Photoshop script that exports to PNG all layers and groups whose names end with ".png".

ps-export-layers-to-png.jsx

#target photoshop
// $.level = 2;

/*
 *  Script by Tomek Cejner (tomek (at) japko dot info)
 *  based on work of Damien van Holten:
 *  http://www.damienvanholten.com/blog/export-groups-to-files-photoshop/
 *
 *  My version adds support of nested layer groups, 
 *  and exports single layers in addition to groups. 
 *
 * supports / in files names
 * export/file.png will be saved in a subfolder named export
 * 
 */

function main(){
    if(!documents.length) return;
    var doc = activeDocument;
    var oldPath = activeDocument.path;
    scanLayerSets(doc);

    function scanLayerSets(el) {
        // find layer groups
        for(var a=0;a<el.layerSets.length;a++){
            if (el.layerSets[a].visible == false) {
                // If the layer is hidden we skip it
                continue
            }
            var lname = el.layerSets[a].name;
            
            if (lname.substr(-4) == ".png") {
                saveLayer(el.layers.getByName(lname), lname, oldPath, true);
                scanLayerSets(el.layerSets[a]);
            } else {
                // recursive
                scanLayerSets(el.layerSets[a]);
            }
        }
        
        // find plain layers in current group whose names end with .png
        for(var j=0; j<el.artLayers.length; j++) {
            var name = el.artLayers[j].name;
            if (name.substr(-4) == ".png") {
                saveLayer(el.layers.getByName(name), name, oldPath, false);
            }
        }
    }   

    function saveLayer(layer, lname, path, shouldMerge) {
        activeDocument.activeLayer = layer;
        dupLayers();
        if (shouldMerge === undefined || shouldMerge === true) {
            activeDocument.mergeVisibleLayers();
        }
        activeDocument.trim(TrimType.TRANSPARENT,true,true,true,true);
        var savePath = path + "/" + lname;
        var saveFile= File(savePath);
        var split_string = SplitPath(savePath);
        var folder = split_string[0];
        
        if (!folder.exists) {
             var outFolder = new Folder(folder);
            outFolder.create();
        }
        SavePNG(saveFile);
        app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
    }

};

main();

function SplitPath(input_path) {
    var split_string = input_path.split('/');
    var file_name = split_string.pop();
    new_path = split_string.join('/')
return [new_path, file_name]
};

function dupLayers() { 
    var desc143 = new ActionDescriptor();
        var ref73 = new ActionReference();
        ref73.putClass( charIDToTypeID('Dcmn') );
    desc143.putReference( charIDToTypeID('null'), ref73 );
    desc143.putString( charIDToTypeID('Nm  '), activeDocument.activeLayer.name );
        var ref74 = new ActionReference();
        ref74.putEnumerated( charIDToTypeID('Lyr '), charIDToTypeID('Ordn'), charIDToTypeID('Trgt') );
    desc143.putReference( charIDToTypeID('Usng'), ref74 );
    executeAction( charIDToTypeID('Mk  '), desc143, DialogModes.NO );
};

function SavePNG(saveFile){
    var pngOpts = new PNGSaveOptions(); 
    pngOpts.compression = 0
    pngOpts.interlaced = false
    activeDocument.saveAs(saveFile, pngOpts, true, Extension.LOWERCASE); 
}