My Android app crashes after few downloaded textures

In my app I download several textures from a server then assign them to sprites or to the new Unity UI Image, it works fine in Editor but on Android the app crashes after few downloaded textures. When I download a texture that will replace another texture I destroy the current sprite in the image because I read somewhere that Unity might be storing the downloaded textures somewhere.

myImage.sprite = Sprite.Create(www.texture, new Rect(0, 0, www.texture.width, www.texture.height), new Vector3(0.5f, .5f));

I found the solution, the answer lies in Resources.UnloadUnusedAssets(). I should call it every time I download a texture and assign it to a sprite.