Android ImageView Fixing Image Size

Try this

ImageView img
    Bitmap bmp;
    int width=100;
    int height=100;
    img=(ImageView)findViewById(R.id.imgView);
    bmp=BitmapFactory.decodeResource(getResources(),R.drawable.image);//image is your image                                                            
    bmp=Bitmap.createScaledBitmap(bmp, width,height, true);
    img.setImageBitmap(bmp);

Or If you want to load complete image size in memory then you can use

<ImageView
    android:id="@+id/img"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:src="@drawable/image" 
    android:scaleType="fitXY"/>

In your case you need to

1. Fix the ImageView's size. You need to use dp unit so that it will look the same in all devices.
2. Set android:scaleType to fitXY

Below is an example:

<ImageView
    android:id="@+id/photo"
    android:layout_width="200dp"
    android:layout_height="100dp"
    android:src="@drawable/iclauncher" 
    android:scaleType="fitXY"/>

For more information regarding ImageView scaleType please refer to the developer website.

You can also try this, suppose if you want to make a back image button and you have "500x500 png" and want it to fit in small button size.

Use dp to fix ImageView's size.

add this line of code to your Imageview.

android:scaleType="fitXY"

EXAMPLE:

<ImageView
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:id="@+id/imageView2"
        android:src="@drawable/Backicon"
        android:scaleType="fitXY"
        />

Fix ImageView's size with dp or fill_parent and set android:scaleType to fitXY.