PHP Manual: image_type_to_mime

function image_type_to_mime_type(int $image_type): string

The image_type_to_mime_type() function will determine the Mime-Type for an IMAGETYPE constant.

The returned values are as follows

**Returned values Constants**
`image_type`	Returned value
`IMAGETYPE_GIF`	`image/gif`
`IMAGETYPE_JPEG`	`image/jpeg`
`IMAGETYPE_PNG`	`image/png`
`IMAGETYPE_SWF`	`application/x-shockwave-flash`
`IMAGETYPE_PSD`	`image/psd`
`IMAGETYPE_BMP`	`image/bmp`
`IMAGETYPE_TIFF_II` (intel byte order)	`image/tiff`
`IMAGETYPE_TIFF_MM` (motorola byte order)	`image/tiff`
`IMAGETYPE_JPC`	`application/octet-stream`
`IMAGETYPE_JP2`	`image/jp2`
`IMAGETYPE_JPX`	`application/octet-stream`
`IMAGETYPE_JB2`	`application/octet-stream`
`IMAGETYPE_SWC`	`application/x-shockwave-flash`
`IMAGETYPE_IFF`	`image/iff`
`IMAGETYPE_WBMP`	`image/vnd.wap.wbmp`
`IMAGETYPE_XBM`	`image/xbm`
`IMAGETYPE_ICO`	`image/vnd.microsoft.icon`
`IMAGETYPE_WEBP`	`image/webp`
`IMAGETYPE_AVIF`	`image/avif`
`IMAGETYPE_HEIF`	`image/heif`

Example #1 image_type_to_mime_type() example

<?php
header("Content-type: " . image_type_to_mime_type(IMAGETYPE_PNG));
?>

Note:
This function does not require the GD image library.

image_type_to_mime_type