Use bitmap options:
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.RGB_565; //Use this if you dont require Alpha channel
options.inSampleSize = 4; // The higher, the smaller the image size and resolution read in
Then set the options in the decode
BitmapFactory.decodeFile(path, options)
Here is a good link to read through, about how to display Bitmaps effciently.
You could even write a method like this to obtain a sized image at your desired resolution.
The following method checks the size the image, then decodes from file, with in-sample size to resize your image from sdcard accordingly, while keeping memory usage at a low.
public static Bitmap decodeSampledBitmapFromFile(string path,
int reqWidth, int reqHeight) { // BEST QUALITY MATCH
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
// Calculate inSampleSize
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
options.inPreferredConfig = Bitmap.Config.RGB_565;
int inSampleSize = 1;
if (height > reqHeight) {
inSampleSize = Math.round((float)height / (float)reqHeight);
}
int expectedWidth = width / inSampleSize;
if (expectedWidth > reqWidth) {
//if(Math.round((float)width / (float)reqWidth) > inSampleSize) // If bigger SampSize..
inSampleSize = Math.round((float)width / (float)reqWidth);
}
options.inSampleSize = inSampleSize;
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(path, options);
}