Added in 0.7.0.

可以提供 URL 嗎？

> they change to php so I can't download successfully

I'm not sure what does it mean, but you can try to turn on "download from cache" option, which sometimes may pass download restriction.

"dateString" variable is added in 0.7.0.

> Q1

No. It's a restriction of Quantum Firefox. Extensions can only download files to Firefox's download folder.

> Q2

See https://github.com/eight04/image-picka#filename-pattern

目前 Image Picka 沒有這樣的功能。你是在哪邊看到這種寫法的？

幫你開了 issue︰
https://github.com/eight04/image-picka/issues/40

[12/29更新]
0.6.1 版加入了簡易的表達式功能。在進階選項中開啟後，就可以使用字串方法來切割字串︰

${name.slice(-2)}${ext}

I would like to know in which situation you would like to change the base number?

How about to change the filename to `chapter1-${index}${ext}` and `chapter2-${index}${ext}`? So they don't overwrite each other and you'll know the chapter number by looking at the filename.

[Edit]
There is a new feature in 0.6.1. Now you can evaluate expressions in filename pattern. To use different base index, turn on the feature in advanced section, and change the pattern to e.g. "${index+20}${ext}" to make it start from 21.

Added in 0.6.0.

Currently Firefox doesn't provide such feature to webextensions, so it is impossible.
https://github.com/eight04/image-picka/issues/14