Android snippet to load images and downscale if needed

ImageUtils.java

import static android.graphics.BitmapFactory.decodeResource;
import static com.google.common.base.Optional.fromNullable;

public static final Double MAX_MEMORY_ALLOCATION = 6E6;

/**
 * This method loads a bitmap from the resources respecting the max memory an image should take in memory
 * @param imageResource
 * @param context
 * @return
 */
public static Optional<Drawable> loadDrawable(@DrawableRes int imageResource, Context context) {
	Optional<Bitmap> candidateBitmap = loadBitmap(imageResource, context);
	Optional<Drawable> candidateDrawable = absent();
	if (candidateBitmap.isPresent()) {
		candidateDrawable = fromNullable((Drawable) new BitmapDrawable(context.getResources(), candidateBitmap.get()));
	}
	return candidateDrawable;
}

/**
 * This method loads a bitmap from the resources respecting the max memory an image should take in memory
 * @param imageResource
 * @param context
 * @return
 */
public static Optional<Bitmap> loadBitmap(@DrawableRes int imageResource, Context context) {
	BitmapFactory.Options scaledOptions = getScaledOptions(imageResource, context, MAX_MEMORY_ALLOCATION);
	if (scaledOptions != null) {
		scaledOptions.inJustDecodeBounds = false;
	}
	return fromNullable(decodeResource(context.getResources(), imageResource, scaledOptions));
}

/**
 * Get the scale factor necessary to make an image take targetMaxMemory
 * @param image
 * @param context
 * @param targetMemory
 * @return
 */
public static BitmapFactory.Options getScaledOptions(@DrawableRes int image, Context context, double targetMemory) {

	int scaleFactor = 1;

	BitmapFactory.Options options = new BitmapFactory.Options();
	options.inJustDecodeBounds = true;

	decodeResource(context.getResources(), image, options);

	int imageHeight = options.outHeight;
	int imageWidth = options.outWidth;

	if (imageHeight != -1 && imageWidth != -1) {
		int bytes = -1;
		switch (options.inPreferredConfig) {
			case ALPHA_8:
				bytes = 1;
				break;
			case ARGB_4444:
			case RGB_565:
				bytes = 2;
				break;
			case ARGB_8888:
				bytes = 4;
				break;
		}

		while (imageWidth * imageHeight * bytes > targetMemory) {
			imageWidth /= 2;
			imageHeight /= 2;
			scaleFactor *= 2;
		}
	}

	options.inSampleSize = scaleFactor;

	return options;
}