[plugin-images] Custom fileTypes config is ignored in processImages function

[noxasch]

This result in its using the default config neglecting user config.

For example if i set additional fileTypes as empty string,

config: {
    fileTypes: [''], // file types in addition to jpeg/png
}

The plugin will still generate webp image ignoring the config.

I already fixed in my fork, but i'm not sure if it's a bug or intentional. I can make a PR for a quick fix.

[nickreese]

Wasn’t intentional. Definitely a side effect of porting my internal tool to the plugin. :) Happy for a PR. (You’re crushing it man)

The important thing I think is that it does the original file format + webp. So maybe the file array documentation should explain that? No reason to generate a jpg of a png when it might have a transparent background.

[noxasch]

@nickreese aha, will do.