Display image from Webform submission using views
This can not be done with webform module alone.
All you need to do is get help of 2 extra modules. 


File Entity
Views Field View


Further you need to do following things. 


Download and enable both of the modules and clear the cache.
Webform is storing file, not only image. I am assuming here you are only uploading image files, you can further get idea to show any type of file there. So go to Image File Type Display: admin/structure/file-types/manage/image/file-display and set the preview/image style. Or if you do not want to change settings for default view mode of the file, download another module Entity View Mode. Go to it's configuration and create specific display and set image style accordingly in file display settings.
Create a view of files, it should be a block. and there add contextual filter for the fid and add field "File: Rendered". You can set file view mode by this field. For your convenience I'm exporting the view below, you just need to import this.



    $view = new view();
    $view->name = 'file_view';
    $view->description = '';
    $view->tag = 'default';
    $view->base_table = 'file_managed';
    $view->human_name = 'File view';
    $view->core = 7;
    $view->api_version = '3.0';
    $view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */

    /* Display: Master */
    $handler = $view->new_display('default', 'Master', 'default');
    $handler->display->display_options['title'] = 'File view';
    $handler->display->display_options['use_more_always'] = FALSE;
    $handler->display->display_options['access']['type'] = 'perm';
    $handler->display->display_options['cache']['type'] = 'none';
    $handler->display->display_options['query']['type'] = 'views_query';
    $handler->display->display_options['exposed_form']['type'] = 'basic';
    $handler->display->display_options['pager']['type'] = 'some';
    $handler->display->display_options['pager']['options']['items_per_page'] = '5';
    $handler->display->display_options['style_plugin'] = 'default';
    $handler->display->display_options['row_plugin'] = 'fields';
    /* Field: File: Name */
    $handler->display->display_options['fields']['filename']['id'] = 'filename';
    $handler->display->display_options['fields']['filename']['table'] = 'file_managed';
    $handler->display->display_options['fields']['filename']['field'] = 'filename';
    $handler->display->display_options['fields']['filename']['label'] = '';
    $handler->display->display_options['fields']['filename']['alter']['word_boundary'] = FALSE;
    $handler->display->display_options['fields']['filename']['alter']['ellipsis'] = FALSE;
    /* Field: File: Rendered */
    $handler->display->display_options['fields']['rendered']['id'] = 'rendered';
    $handler->display->display_options['fields']['rendered']['table'] = 'file_managed';
    $handler->display->display_options['fields']['rendered']['field'] = 'rendered';
    $handler->display->display_options['fields']['rendered']['label'] = '';
    $handler->display->display_options['fields']['rendered']['element_label_colon'] = FALSE;
    /* Contextual filter: File: File ID */
    $handler->display->display_options['arguments']['fid']['id'] = 'fid';
    $handler->display->display_options['arguments']['fid']['table'] = 'file_managed';
    $handler->display->display_options['arguments']['fid']['field'] = 'fid';
    $handler->display->display_options['arguments']['fid']['default_action'] = 'default';
    $handler->display->display_options['arguments']['fid']['default_argument_type'] = 'node';
    $handler->display->display_options['arguments']['fid']['summary']['number_of_records'] = '0';
    $handler->display->display_options['arguments']['fid']['summary']['format'] = 'default_summary';
    $handler->display->display_options['arguments']['fid']['summary_options']['items_per_page'] = '25';

    /* Display: Single File View */
    $handler = $view->new_display('block', 'Single File View', 'block');


Now in your main view (where you are showing submissions). Add a new relationship for Webform submissions: Data. You'll need to set the nid for the webform here and select the image component. 
Add new field to the view submission data: Value (raw). This will give you the file_id for the associated file. Exclude it from display.
Add another field Global: View. Select the view you imported and the block display. In contextual filter set [!data] from replacement patterns. It was the raw value of the field which you excluded from the display. And Here you go, save the view and rock :). Thanks for asking such good question. Still if you face any problem during this tutorial, ask me.