Previously if upload had missing width and height we would calculate
on first use BUT we (me) forgot to save this to the database
This was particularly bad on home page cause category images (when old)
miss dimensions.
This generates a 10x10 PNG thumbnail for each lightboxed image.
If Image Lazy Loading is enabled (IntersectionObserver API) then
we'll load the low res version when offscreen. As the image scrolls
in we'll swap it for the high res version.
We use a WeakMap to track the old image attributes. It's much less
memory than storing them as `data-*` attributes and swapping them
back and forth all the time.
For a normal upload url
Before
```
Warming up --------------------------------------
264.000 i/100ms
Calculating -------------------------------------
2.754k (± 8.4%) i/s - 13.728k in 5.022066s
```
After
```
Warming up --------------------------------------
341.000 i/100ms
Calculating -------------------------------------
3.435k (±11.6%) i/s - 17.050k in 5.045676s
```
Previously we used width and height for thumbnails, new code ensures
1. We auto correct width and height
2. We added extra columns for thumbnail_width and height, this is determined
by actual upload and no longer passed in as a side effect
3. Optimized Image now stores filesize which can be used for analysis, decisions
Also
- fixes Android image manifest as a side effect
- fixes issue where a thumbnail generated that is smaller than the upload is no longer used
* `rescue nil` is a really bad pattern to use in our code base.
We should rescue errors that we expect the code to throw and
not rescue everything because we're unsure of what errors the
code would throw. This would reduce the amount of pain we face
when debugging why something isn't working as expexted. I've
been bitten countless of times by errors being swallowed as a
result during debugging sessions.
This refactors handling of s3 so it can be specified via GlobalSetting
This means that in a multisite environment you can configure s3 uploads
without actual sites knowing credentials in s3
It is a critical setting for situations where assets are mirrored to s3.
