Function getBase64ImageMIMEType

getBase64ImageMIMEType(
    str:
        | `data:image/gif;base64,${string}`
        | `data:image/jpeg;base64,${string}`
        | `data:image/jpg;base64,${string}`
        | `data:image/png;base64,${string}`
        | `data:image/svg+xml;base64,${string}`
        | `data:image/webp;base64,${string}`,
): | "image/gif"
| "image/jpeg"
| "image/jpg"
| "image/png"
| "image/svg+xml"
| "image/webp"
get the mime type of a base64 image.
Parameters
- str:
      | `data:image/gif;base64,${string}`
      | `data:image/jpeg;base64,${string}`
      | `data:image/jpg;base64,${string}`
      | `data:image/png;base64,${string}`
      | `data:image/svg+xml;base64,${string}`
      | `data:image/webp;base64,${string}`
Returns
    | "image/gif"
    | "image/jpeg"
    | "image/jpg"
    | "image/png"
    | "image/svg+xml"
    | "image/webp"
Example
```
import { assertEquals } from "jsr:@std/assert"

const
	img_uri = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAD...",
	img_mime = getBase64ImageMIMEType(img_uri)

assertEquals(img_mime, "image/png")
```
- Defined in work/kitchensink_ts/kitchensink_ts/src/image.ts:100