Reduce Application Binary Size

[jkmassel]

In #22296, we merged a very large PDF file as an xcassets resource.

This increased the binary size by 43.1MB, causing it to be too large for installation or update on cellular networks.

This PR resolves that by:

1. Switching out the PDF file for a JPEG-compressed gradient. If I'd had more time, I would've probably generated the gradient in code instead of as a static image, but that can be left for another day.
2. Running perceptually invisible compression on all PNG assets (which saves another 0.5 MB)

To test:

Regression Notes

1. Potential unintended areas of impact

• Modifies many icon images – use the left/right comparison on GitHub to note that they're visually indistinguishable.
• Run the first-launch process, note that there's no user-visible difference.

3. What I did to test those areas of impact (or what existing automated tests I relied on)

• I did the items above.

4. What automated tests I added (or what prevented me from doing so)

• No automated tests available for this.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

Testing checklist:

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• VoiceOver.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• iPhone and iPad.
• Multi-tasking: Split view and Slide over. (iPad)

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 25.0 ❄️. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

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	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr23261-aca7b63
	Version	25.0
	Bundle ID	org.wordpress.alpha
	Commit	aca7b63
	App Center Build	WPiOS - One-Offs #10011

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📲 You can test the changes from this Pull Request in Jetpack Alpha by scanning the QR code below to install the corresponding build.

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr23261-aca7b63
	Version	25.0
	Bundle ID	com.jetpack.alpha
	Commit	aca7b63
	App Center Build	jetpack-installable-builds #9062

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[guarani]

Thanks @jkmassel!

I realized the Stats PDF isn't used, so it can be removed.

I tested the other change to the welcome screen and noticed it looks odd in dark mode:

this branch	trunk

[guarani]

@jkmassel, this resource is unused and can be removed entirely.
We removed the screen that used it in #19917, but the PDF was overlooked.

[jkmassel]

Great! Addressed in ac03070

[alpavanoglu]

Hey @jkmassel

This increased the binary size by 43.1MB

So that I have a better understanding and avoid this kind of thing in the future, how does that pdf file increase the binary size by 43.1 Megabytes when the file itself appear to be 5 Kilobytes? I understand the vector file will be converted but still the number is extremely high indeed.

If you mean the gradient, shouldn't the trade there lower the size rather than increase it?

[jkmassel]

@alpavanoglu – I'm not sure I understand?

how does that pdf file increase the binary size by 43.1 Megabytes when the file itself appear to be 5 Kilobytes

Where did you get 5kb from? The binary size is increased so much because the 7 MB PDF file is converted to a 3x, 2x, and 1x PNG by Xcode during compilation. The resulting Assets.car file is duplicated in the App Binary – it's also part of WordPressShareExtension, WordPressDraftActionExtension, andJetpackIntents, so the cost has to be paid four times.

If you mean the gradient, shouldn't the trade there lower the size rather than increase it?

Interesting – I suspected #22296 because removing this file reduced the binary size by the 43 MB and we got a notification from Apple on Feb 20 that the app had exceeded the download limit. Perhaps there is another factor at play?

[jkmassel]

Thanks @guarani – the transparency adds a bunch of complexity – the issue should now be resolved. Unfortunately the savings aren't quite as dramatic as with a JPEG but it's a good start. Brings down the Jetpack binary size from 269.8MB to 210.6MB, so we're much closer to the cellular limit now!

[alpavanoglu]

@jkmassel

Where did you get 5kb from?

That PR added 1 PDF and replaced the other. The pure addition is the small one I referred to there. And the replaced PDF is smaller in size so I reckoned overall I would be reducing the size and not increase it.

Perhaps there is another factor at play?

Perhaps. I wanted to clarify to avoid such things in the future.

[jkmassel]

Addressed in #23381