Rating:
Provided file is with useless extension `chr` and ouptut of file provide no additional help, but examinig the first couple of bytes provide with hint that could be `PNG` file.
First bytes look like scrambled `PNG` and `IHDR` the header and first chuck of the `PNG` file.
The proper bytes are
[List of file signatures - Wikipedia](https://en.wikipedia.org/wiki/List_of_file_signatures)
After changing header in hexeditor
`file` still do not recognize it as `PNG` but `pngcheck` does and provide with additional data
To repair that chunk we need to change the blue-makred bytes because 4 bytes before(marked red underline) is length of `IHDR` chunk
After changing bytes to be `IHDR`
`pngcheck` complains about `IHDR` legnth
`IHDR` chunk contains various information
```
Width: 4 bytes
Height: 4 bytes
Bit depth: 1 byte
Color type: 1 byte
Compression method: 1 byte
Filter method: 1 byte
Interlace method: 1 byte
```
And all this adds to 13 bytes so `0xD` in hex so we set that value in the length of `IHDR` chunk
After that change there is no more errors, `file` recognize this file as `PNG` and `pngcheck` says there everything allright
And this is the flag
