php - getimagesize returns bool(false) -

i have created wordpress plugin can choose file media uploader:

    <input type="text" id="clb_setting_logo" name="clb_plugin_options[clb_setting_logo]" value="<?php echo esc_url( $options['clb_setting_logo'] ); ?>" />     <input id="upload_logo_button" type="button" class="button" value="<?php _e( 'choose image', 'clb' ); ?>" />     <span class="description"><?php _e('choose image button.', 'clb' ); ?></span> 

when choose image media uploader path taken field #clb_setting_logo can seen above.

within function try access dimensions this:

if (!empty($options['clb_setting_logo'])) {     $imagesize = getimagesize($options['clb_setting_logo']); 

it runs on 2 servers, on server getimagesize returns bool(false), why? first thought happens because normal file path taken - this: "http://exmaple.com/wp-content/uploads/2016/02/test.png" - works on other installations.

does know something? thanks!