[Finishes #89571400, #101057628] Pixelation "Save Image" bugs
[Finishes #89571400, #101057628] Pixelation "Save Image" bugs

Fixes:
 - Remove gray borders from saved pixelation image
 - Clicking "Save Image" in pixelation widget opens empty pop-up in IE

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dillia23/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org