How can I set image size in media manager to “Full Size” as default

ok.
HANDLE WITH CARE AND BACKUP YOUR FILES BEFORE DOING THAT .
what you look for is not in media.php but in upload.js inside js folder inside wp-admin folder. around line 126.

and in file script-loader.php inside wp-includes folder around line 130 you will find this :

'thumb' => __('Thumbnail'),
'full' => __('Full size'),
'icon' => __('Icon'),
'title' => __('Title'),

this givees a “name” to the options for the jscript.

Modify on your own risk

Hi thanks for the response, I have looked at upload.js and I cant work out what I need to do. There is no mention of “medium” anywhere in upload.js or script-loader.php, only full and thumb.

Are these the lines I should focus on?

var display = [];
			var checkedDisplay = 'display-title';
			if ( 1 == this.currentImage.isImage ) {
				checkedDisplay = 'display-full';
				if ( this.currentImage.thumb ) {
					display.push("<label for='display-thumb'><input type='radio' name='display' id='display-thumb' value='thumb' /> " + this.thumb + "</label>");
					checkedDisplay = 'display-thumb';
				}
				display.push("<label for='display-full'><input type='radio' name='display' id='display-full' value='full' /> " + this.full + "</label>");
			} else if ( this.currentImage.thumb ) {
				display.push("<label for='display-thumb'><input type='radio' name='display' id='display-thumb' value='thumb' /> " + this.icon + "</label>");
			}
			if ( display.length ) {
				display.push("<label for='display-title'><input type='radio' name='display' id='display-title' value='title' /> " + this.title + "</label>");
				h += "<tr><th style='padding-bottom:.5em'>" + this.show + "</th><td style='padding-bottom:.5em'>";
				jQuery(display).each( function() { h += this; } );
				h += "</td></tr>";
			}

Found this topic looking for the same solution. Kujina, you were right from the start! I was able to change the default size in wp-admin/includes/media.php, in the following section: (starting line 452)

$form_fields['image-size'] = array(
			'label' => __('Size'),
			'input' => 'html',
			'html'  => "
				" . ( $thumb ? "<input type='radio' name='attachments[$post->ID][image-size]' id='image-size-thumb-$post->ID' value='thumbnail' />
				<label for='image-size-thumb-$post->ID'>" . __('Thumbnail') . "</label>
				" : '' ) . "<input type='radio' name='attachments[$post->ID][image-size]' id='image-size-medium-$post->ID' value='medium' checked='checked' />
				<label for='image-size-medium-$post->ID'>" . __('Medium') . "</label>
				<input type='radio' name='attachments[$post->ID][image-size]' id='image-size-full-$post->ID' value='full' />
				<label for='image-size-full-$post->ID'>" . __('Full size') . "</label>",
		);

just move the checked=’checked’ attribute to the option you want to be the default. You can also change the default image alignment, it’s a few lines up.

Hope that helps. It would be nice to see this as a configuration option in future releases ??

Sweet. Editing the media.php worked a charm for me too. What about removing the automatic link? Suggestions there?

Tnx for the solution!