dynamically add pictures to gallery widget

“new image resources”?

Image resources are a part of /res/drawable folder inside your .apk application package. You can not add “new” image resources during runtime.

Is there some other use case you had in mind?

Edited after posters explanation:

You have to add media files to Media Store in order to be seen by gallery widget. Use MediaScanner. I use this convenient wrapper in my code:

public class MediaScannerWrapper implements  
MediaScannerConnection.MediaScannerConnectionClient {
    private MediaScannerConnection mConnection;
    private String mPath;
    private String mMimeType;

    // filePath - where to scan; 
    // mime type of media to scan i.e. "image/jpeg". 
    // use "*/*" for any media
    public MediaScannerWrapper(Context ctx, String filePath, String mime){
        mPath = filePath;
        mMimeType = mime;
        mConnection = new MediaScannerConnection(ctx, this);
    }

    // do the scanning
    public void scan() {
        mConnection.connect();
    }

    // start the scan when scanner is ready
    public void onMediaScannerConnected() {
        mConnection.scanFile(mPath, mMimeType);
        Log.w("MediaScannerWrapper", "media file scanned: " + mPath);
    }

    public void onScanCompleted(String path, Uri uri) {
        // when scan is completes, update media file tags
    }
}

Then instantiate MediaScannerWrapper and start it with scan(). You could tweak it to handle more than one file at the time. Hint: pass List of File paths, and then loop around mConnection.scanFile.