ShareImages.java

private void shareImage(Bitmap bitmap){
	// save bitmap to cache directory
	try {
		File cachePath = new File(this.getCacheDir(), "images");
		cachePath.mkdirs(); // don't forget to make the directory
		FileOutputStream stream = new FileOutputStream(cachePath + "/image.png"); // overwrites this image every time
		bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
		stream.close();

	} catch (IOException e) {
		e.printStackTrace();
	}
	File imagePath = new File(this.getCacheDir(), "images");
	File newFile = new File(imagePath, "image.png");
	Uri contentUri = FileProvider.getUriForFile(this, BuildConfig.APPLICATION_ID + ".fileprovider", newFile);

	if (contentUri != null) {
		Intent shareIntent = new Intent();
		shareIntent.setAction(Intent.ACTION_SEND);
		shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); // temp permission for receiving app to read this file
		shareIntent.setDataAndType(contentUri, getContentResolver().getType(contentUri));
		shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri);
		shareIntent.setType("image/png");
		startActivity(Intent.createChooser(shareIntent, "Choose an app"));
	}
}