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copied!<p>This is pretty memory intensive. The base64 <code>string</code>, the <code>byte[]</code> array, the <code>NSData</code>, the <code>UIImage</code>, the second <code>NSData</code>, the second <code>byte[]</code> array. That's many times the required memory of the image you're working on.</p> <p>Depending on how the code is called (e.g. a loop over a bunch of images) you might be allocating memory faster than the GC is able to reclaim it. At some point iOS will trigger a memory warning (but that won't help in a loop) and it will kill you if memory usage is not rapidly reduced.</p> <p>You can easily lower your memory requirement by disposing of every <code>IDisposable</code> instance your code create. Right now you're disposing only one of the two <code>NSData</code> instances you create and you're not disposing of the <code>UIImage</code>. You could dispose of all of them like this:</p> <pre><code>byte[] encodedDataAsBytes = Convert.FromBase64String ( base64String ); using (var nsd1 = NSData.FromArray ( encodedDataAsBytes )) using (var img = UIImage.LoadFromData ( nsd1 )) using (NSData data = img.AsPNG ()) { byte[] returnBytes2 = new byte [data.Length]; Marshal.Copy (data.Bytes, returnBytes2, 0, (int) data.Length); return returnBytes2; } </code></pre> <p>Next, what's the purpose of the code later on ? i.e. what are you doing with the <code>byte[]</code> containing the PNG image ? It's not very useful by itself, but if you're only saving it to disk then you could do so from the <code>NSData</code> and skip the last <code>byte[]</code> allocation. </p> <p>Other tricks, usage dependent, could also be applied (e.g. reusing the second <code>byte[]</code> buffer when possible) but we would need to know more about how the code is being used.</p>

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