Why do we optimize our images with software like ImageOptim?

Answer: C

As images can often contain unnecessary data, optimizing them reduces the file size so they download quicker to the user of our iAd.

What tool should you use in Preview to remove a solid block of color to make part of an image transparent?

Answer: B

Instant Alpha is correct; it’s called this because alpha is often used as a term for the level of transparency an image has.

Which image format should you use whenever you can?

Answer: A

You should use JPEGs whenever you can; they’re able to be compressed to keep their file size down.

When would you need to use a PNG image?

Answer: B

You’d use a PNG when you have a transparent ‘see through’ section of an image, as JPEG doesn’t support transparency. Other times you’d use PNG, including for images with text or crisp line art, and images with large blocks of color.

What audio format should you convert your sound files to?

Answer: B

m4a audio files use AAC, which iOS devices are able to decode quickly and efficiently.

What does the ‘reference movie’ created by QuickTime do?

Answer: C

The reference movie selects the optimal version of your video depending on the user’s bandwidth. This ensures users on high bandwidth connections see the best quality video available, and users on slower networks don’t spend needless time waiting for content to load.