I’ve been trying to figure this out for a long time and can never get any help on the Wordpress plugin forum. 
Hopefully you guys can help me out here…
I’m trying to create a plugin where users can upload an image.
WordPress already has a built in image uploader and manipulator - so how do I instantiate it and utilize it in my plugin?
Yeah that’s definitely a start! Thank you.
What I’m really hoping to accomplish is something similar to what you see when you create a new Post. Above the description box, there’s the text that says “Upload/Insert”, and then you have the little icon next to it for adding an Image.
I want to simply use that in my plugin. When a person clicks on the icon for “image”, the overlay box pops up and I get the upload screen where I can upload the image and then select the image i want to use.
Thanks for any assistance 
Maybe you want the wp-admin/media-upload.php file?
/**
* Manage media uploaded file.
*
* There are many filters in here for media. Plugins can extend functionality
* by hooking into the filters.
*
* @package WordPress
* @subpackage Administration
*/
I believe the file you’re interested in using is the wp-includes/media.php file?
If so it has ~42 functions
class WP_Embed
function __construct()
function _wp_post_thumbnail_class_filter( $attr )
function _wp_post_thumbnail_class_filter_add( $attr )
function _wp_post_thumbnail_class_filter_remove( $attr )
function add_image_size( $name, $width = 0, $height = 0, $crop = FALSE )
function adjacent_image_link($prev = true, $size = 'thumbnail', $text = false)
function autoembed( $content )
function autoembed_callback( $match )
function cache_oembed( $post_ID )
function delete_oembed_caches( $post_ID )
function gallery_shortcode($attr)
function gd_edit_image_support($mime_type)
function get_attachment_taxonomies($attachment)
function get_image_tag($id, $alt, $title, $align, $size='medium')
function image_constrain_size_for_editor($width, $height, $size = 'medium')
function image_downsize($id, $size = 'medium')
function image_get_intermediate_size($post_id, $size='thumbnail')
function image_hwstring($width, $height)
function image_make_intermediate_size($file, $width, $height, $crop=false)
function image_resize( $file, $max_w, $max_h, $crop = false, $suffix = null, $dest_path = null, $jpeg_quality = 90 )
function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = false)
function img_caption_shortcode($attr, $content = null)
function maybe_make_link( $url )
function maybe_run_ajax_cache()
function next_image_link($size = 'thumbnail', $text = false)
function previous_image_link($size = 'thumbnail', $text = false)
function register_handler( $id, $regex, $callback, $priority = 10 )
function run_shortcode( $content )
function set_post_thumbnail_size( $width = 0, $height = 0, $crop = FALSE )
function shortcode( $attr, $url = '' )
function unregister_handler( $id, $priority = 10 )
function wp_constrain_dimensions( $current_width, $current_height, $max_width=0, $max_height=0 )
function WP_Embed()
function wp_embed_defaults()
function wp_embed_register_handler( $id, $regex, $callback, $priority = 10 )
function wp_embed_unregister_handler( $id, $priority = 10 )
function wp_expand_dimensions( $example_width, $example_height, $max_width, $max_height )
function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false, $attr = '')
function wp_get_attachment_image_src($attachment_id, $size='thumbnail', $icon = false)
function wp_imagecreatetruecolor($width, $height)
function wp_oembed_add_provider( $format, $provider, $regex = false )
function wp_oembed_get( $url, $args = '' )
And these Codex links might help
http://codex.wordpress.org/Using_Image_and_File_Attachments
http://codex.wordpress.org/Function_Reference/image_downsize
Just bumping in hopes of getting an answer
I’ve looked at other plugins that utilize image uploading, but they all use their own script to upload, resize, and crop the image…but it just seems like re-inventing the wheel. WP already has this functionality - I just want to utilize it.
Thanks