Repository: yt-dlp
Issue: preserve thumbnail filenames
Labels: enhancement,triage

### DO NOT REMOVE OR SKIP THE ISSUE TEMPLATE

- [X] I understand that I will be **blocked** if I *intentionally* remove or skip any mandatory\* field

### Checklist

- [X] I'm asking a question and **not** reporting a bug or requesting a feature
- [X] I've looked through the [README](https://github.com/yt-dlp/yt-dlp#readme)
- [X] I've verified that I'm running yt-dlp version **2023.03.04** ([update instructions](https://github.com/yt-dlp/yt-dlp#update)) or later (specify commit)
- [X] I've searched [known issues](https://github.com/yt-dlp/yt-dlp/issues/3766) and the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar questions **including closed ones**. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)

### Please make sure the question is worded well enough to be understood

How is it possible to preserve the original thumbnail filenames when using `--write-all-thumbnails` ?
What output template for `-o "thumbnail:"` is required ?

I'd like to download/save the thumbnails as hqdefault.webp, sddefault.webp, maxresdefault.webp, etc. as listed below.

### Provide verbose output that clearly demonstrates the problem

- [X] Run **your** yt-dlp command with **-vU** flag added (`yt-dlp -vU <your command line>`)
- [X] If using API, add `'verbose': True` to `YoutubeDL` params instead
- [X] Copy the WHOLE output (starting with `[debug] Command-line config`) and insert it below

### Complete Verbose Output

```shell
[info] Available thumbnails for gr51aVj-mLg:
ID Width   Height  URL
0  unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/3.jpg
1  unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/3.webp
2  unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/2.jpg
3  unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/2.webp
4  unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/1.jpg
5  unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/1.webp
6  unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/mq3.jpg
7  unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/mq3.webp
8  unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/mq2.jpg
9  unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/mq2.webp
10 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/mq1.jpg
11 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/mq1.webp
12 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/hq3.jpg
13 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/hq3.webp
14 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/hq2.jpg
15 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/hq2.webp
16 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/hq1.jpg
17 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/hq1.webp
18 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/sd3.jpg
19 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/sd3.webp
20 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/sd2.jpg
21 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/sd2.webp
22 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/sd1.jpg
23 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/sd1.webp
24 120     90      https://i.ytimg.com/vi/gr51aVj-mLg/default.jpg
25 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/default.webp
26 320     180     https://i.ytimg.com/vi/gr51aVj-mLg/mqdefault.jpg
27 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/mqdefault.webp
28 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/0.jpg
29 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/0.webp
30 168     94      https://i.ytimg.com/vi/gr51aVj-mLg/hqdefault.jpg?sqp=-oaymwEbCKgBEF5IVfKriqkDDggBFQAAiEIYAXABwAEG&rs=AOn4CLB2tSjPacpmi_j9_RDFFmZDqACpBw
31 196     110     https://i.ytimg.com/vi/gr51aVj-mLg/hqdefault.jpg?sqp=-oaymwEbCMQBEG5IVfKriqkDDggBFQAAiEIYAXABwAEG&rs=AOn4CLD1DDbbtvl9UtTgTtGSd_w2BWUjww
32 246     138     https://i.ytimg.com/vi/gr51aVj-mLg/hqdefault.jpg?sqp=-oaymwEcCPYBEIoBSFXyq4qpAw4IARUAAIhCGAFwAcABBg==&rs=AOn4CLC2hr9_gO7ldTwVQCifPG5EJQxLdQ
33 336     188     https://i.ytimg.com/vi/gr51aVj-mLg/hqdefault.jpg?sqp=-oaymwEcCNACELwBSFXyq4qpAw4IARUAAIhCGAFwAcABBg==&rs=AOn4CLA2lRmid5G4tBNajFFI5HNuF1JPUQ
34 480     360     https://i.ytimg.com/vi/gr51aVj-mLg/hqdefault.jpg
35 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/hqdefault.webp
36 640     480     https://i.ytimg.com/vi/gr51aVj-mLg/sddefault.jpg
37 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/sddefault.webp
38 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/hq720.jpg
39 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/hq720.webp
40 unknown unknown https://i.ytimg.com/vi/gr51aVj-mLg/maxresdefault.jpg
41 unknown unknown https://i.ytimg.com/vi_webp/gr51aVj-mLg/maxresdefault.webp
```