NEW: Add caching of images 💯

[marianrick]

Enables caching of already optimized images to skip them within the next run.

[ahmadawais]

@marianrick
Glad to have you here as a contributor!

That looks interesting, but I had concerns that cache itself built several copies, the last time I used it, and that started messing up with the git repo. How does this work? Care to explain it? Or I will spend some time to study the cache module later this week.

[marianrick]

@ahmadawais glad to hear, that you are interested in these kind of improvements.

While I would love to provide further information about the use of gulp-cache with imagemin, I have to admit, that I am far from being an expert. I tried to look for some detailed information, but most of the time I have found outdated threads and bug reports.

To keep this repo as a high quality WPGulp task, I think I cannot provide you with further information about it, as I do not have enough expertise. If you have got the time to test it and make a decision as skilled developer, it sounds like a good idea. Otherwise maybe another person can contribute some details within this thread :)

[ahmadawais]

@marianrick That's great.
I am very happy to see people care enough to contribute back. And your contributions to the documentation look very much inline and high quality.

Let's leave this here for a while for others to look at and comment, until unless I can get back to it.

[JeremyEnglert]

@marianrick great idea! I hate waiting for already optimized images to re-run.

@ahmadawais I'm working on using Gulp 4's features to improve caching across the entire project (styles, images, scripts).

It looks like this PR currently has conflicts. But I'd be happy to incorporate these changes in my work.

[ahmadawais]

Thanks for this PR @marianrick I had to implement it myself since we are only accepting PR's against v2.0.0 branch. But keep 'em coming.