Icon is flipped horizontally when icon-anchor is *-left or *-right and icon loaded via addImage()

Nobody has claimed this yet.

I load an image using `addImage` and `loadImage`. When using `icon-anchor: center` it displays normally:


However when I use `icon-anchor: left` (or `right`, `bottom-left` etc) it:

- flips the image along the vertical axis
- positions the image to the left of its anchor
- horizontally compresses the image


In these examples, the location of the feature is the bottom left corner of the cream-colored rectangle (ignoring the rounded corner).

This does not occur when using an image from a pre-generated sprite sheet (eg, `parking-11`):


My layer definition here is:

```
{
"id": "cad-logo",
"type": "symbol",
"source": "cad",
"minzoom": 13,
"filter": [
"==",
[
"get",
"layer"
],
"_LOGO"
],
"layout": {
"icon-image": "landnow-logo",
"icon-anchor": "left",
"icon-size": 0.2
}
}
```

There is no mention of flipping behaviour in the documentation, and the fact that it doesn't happen with a pre-generated stylesheet suggests that this is a bug, not intended.

Using v3.0.1. Also present in v2.13.0.

The reported entry points are addImage(), loadImage(), and the symbol layer's icon-anchor and icon-image properties; no source file or test is named. Start by reproducing the issue with a dynamically loaded image and compare it with the pre-generated sprite case. Done means left, right, and corner anchors preserve orientation, dimensions, and placement consistently.

Written by the indexing model from the issue text.