je vous remercie infiniment pour vos réponses.
J'ai essayé de suivre votre solution mais j'ai des problèmes d'upload des images : je ne peux ni les ajouter ni les supprimer.
Voilà l'erreur qui s'affiche lors du survol:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <meta name="robots" content="noindex,nofollow" /> <style> /* Copyright (c) 2010, Yahoo! Inc. All rights reserved. Code licensed under the BSD License: http://developer.yahoo.com/yui/license.html */ html{color:#000;background:#FFF;}body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,textarea,p,blockquote,th,td{margin:0;padding:0;}table{border-collapse:collapse;border-spacing:0;}fieldset,img{border:0;}address,caption,cite,code,dfn,em,strong,th,var{font-style:normal;font-weight:normal;}li{list-style:none;}caption,th{text-align:left;}h1,h2,h3,h4,h5,h6{font-size:100%;font-weight:normal;}q:before,q:after{content:'';}abbr,acronym{border:0;font-variant:normal;}sup{vertical-align:text-top;}sub{vertical-align:text-bottom;}input,textarea,select{font-family:inherit;font-size:inherit;font-weight:inherit;}input,textarea,select{*font-size:100%;}legend{color:#000;} html { background: #eee; padding: 10px } img { border: 0; } #sf-resetcontent { width:970px; margin:0 auto; } .sf-reset { font: 11px Verdana, Arial, sans-serif; color: #333 } .sf-reset .clear { clear:both; height:0; font-size:0; line-height:0; } .sf-reset .clear_fix:after { display:block; height:0; clear:both; visibility:hidden; } .sf-reset .clear_fix { display:inline-block; } .sf-reset * html .clear_fix { height:1%; } .sf-reset .clear_fix { display:block; } .sf-reset, .sf-reset .block { margin: auto } .sf-reset abbr { border-bottom: 1px dotted #000; cursor: help; } .sf-reset p { font-size:14px; line-height:20px; color:#868686; padding-bottom:20px } .sf-reset strong { font-weight:bold; } .sf-reset a { color:#6c6159; cursor: default; } .sf-reset a img { border:none; } .sf-reset a:hover { text-decoration:underline; } .sf-reset em { font-style:italic; } .sf-reset h1, .sf-reset h2 { font: 20px Georgia, "Times New Roman", Times, serif } .sf-reset .exception_counter { background-color: #fff; color: #333; padding: 6px; float: left; margin-right: 10px; float: left; display: block; } .sf-reset .exception_title { margin-left: 3em; margin-bottom: 0.7em; display: block; } .sf-reset .exception_message { margin-left: 3em; display: block; } .sf-reset .traces li { font-size:12px; padding: 2px 4px; list-style-type:decimal; margin-left:20px; } .sf-reset .block { background-color:#FFFFFF; padding:10px 28px; margin-bottom:20px; -webkit-border-bottom-right-radius: 16px; -webkit-border-bottom-left-radius: 16px; -moz-border-radius-bottomright: 16px; -moz-border-radius-bottomleft: 16px; border-bottom-right-radius: 16px; border-bottom-left-radius: 16px; border-bottom:1px solid #ccc; border-right:1px solid #ccc; border-left:1px solid #ccc; } .sf-reset .block_exception { background-color:#ddd; color: #333; padding:20px; -webkit-border-top-left-radius: 16px; -webkit-border-top-right-radius: 16px; -moz-border-radius-topleft: 16px; -moz-border-radius-topright: 16px; border-top-left-radius: 16px; border-top-right-radius: 16px; border-top:1px solid #ccc; border-right:1px solid #ccc; border-left:1px solid #ccc; overflow: hidden; word-wrap: break-word; } .sf-reset a { background:none; color:#868686; text-decoration:none; } .sf-reset a:hover { background:none; color:#313131; text-decoration:underline; } .sf-reset ol { padding: 10px 0; } .sf-reset h1 { background-color:#FFFFFF; padding: 15px 28px; margin-bottom: 20px; -webkit-border-radius: 10px; -moz-border-radius: 10px; border-radius: 10px; border: 1px solid #ccc; } </style> </head> <body> <div id="sf-resetcontent" class="sf-reset"> <h1>Whoops, looks like something went wrong.</h1> <h2 class="block_exception clear_fix"> <span class="exception_counter">1/1</span> <span class="exception_title"><abbr title="LogicException">LogicException</abbr> in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-foundation\Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser.php line 127" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">MimeTypeGuesser.php line 127</a>:</span> <span class="exception_message">Unable to guess the mime type as no guessers are available (Did you enable the php_fileinfo extension?)</span> </h2> <div class="block"> <ol class="traces list_exception"> <li> in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-foundation\Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser.php line 127" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">MimeTypeGuesser.php line 127</a></li> <li>at <abbr title="Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser">MimeTypeGuesser</abbr>->guess('C:\xampp\tmp\php1E52.tmp') in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-foundation\Symfony\Component\HttpFoundation\File\File.php line 87" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">File.php line 87</a></li> <li>at <abbr title="Symfony\Component\HttpFoundation\File\File">File</abbr>->getMimeType() in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Controller\Admin\FileController.php line 143" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">FileController.php line 143</a></li> <li>at <abbr title="Thelia\Controller\Admin\FileController">FileController</abbr>->processImage(<em>object</em>(<abbr title="Symfony\Component\HttpFoundation\File\UploadedFile">UploadedFile</abbr>), '1', 'category', 'image', <em>array</em>('image/jpeg' => <em>array</em>('jpg', 'jpeg'), 'image/png' => <em>array</em>('png'), 'image/gif' => <em>array</em>('gif')), <em>array</em>()) in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Controller\Admin\FileController.php line 94" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">FileController.php line 94</a></li> <li>at <abbr title="Thelia\Controller\Admin\FileController">FileController</abbr>->saveFileAjaxAction('1', 'category', 'image', <em>array</em>('image/jpeg' => <em>array</em>('jpg', 'jpeg'), 'image/png' => <em>array</em>('png'), 'image/gif' => <em>array</em>('gif')), <em>array</em>()) in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Controller\Admin\FileController.php line 250" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">FileController.php line 250</a></li> <li>at <abbr title="Thelia\Controller\Admin\FileController">FileController</abbr>->saveImageAjaxAction('1', 'category')</li> <li>at <abbr title=""></abbr>call_user_func_array(<em>array</em>(<em>object</em>(<abbr title="Thelia\Controller\Admin\FileController">FileController</abbr>), 'saveImageAjaxAction'), <em>array</em>('1', 'category')) in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-kernel\Symfony\Component\HttpKernel\HttpKernel.php line 117" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">HttpKernel.php line 117</a></li> <li>at <abbr title="Symfony\Component\HttpKernel\HttpKernel">HttpKernel</abbr>->handleRaw(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1') in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-kernel\Symfony\Component\HttpKernel\HttpKernel.php line 61" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">HttpKernel.php line 61</a></li> <li>at <abbr title="Symfony\Component\HttpKernel\HttpKernel">HttpKernel</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1', <em>true</em>) in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Core\TheliaHttpKernel.php line 78" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">TheliaHttpKernel.php line 78</a></li> <li>at <abbr title="Thelia\Core\TheliaHttpKernel">TheliaHttpKernel</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1', <em>true</em>) in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Core\Stack\ParamInitMiddleware.php line 86" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">ParamInitMiddleware.php line 86</a></li> <li>at <abbr title="Thelia\Core\Stack\ParamInitMiddleware">ParamInitMiddleware</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1', <em>true</em>) in <a title="C:\xampp\htdocs\printdesign\vendor\thelia\core\lib\Thelia\Core\Stack\SessionMiddleware.php line 80" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">SessionMiddleware.php line 80</a></li> <li>at <abbr title="Thelia\Core\Stack\SessionMiddleware">SessionMiddleware</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1', <em>true</em>) in <a title="C:\xampp\htdocs\printdesign\vendor\stack\builder\src\Stack\StackedHttpKernel.php line 23" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">StackedHttpKernel.php line 23</a></li> <li>at <abbr title="Stack\StackedHttpKernel">StackedHttpKernel</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>), '1', <em>true</em>) in <a title="C:\xampp\htdocs\printdesign\vendor\symfony\http-kernel\Symfony\Component\HttpKernel\Kernel.php line 188" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">Kernel.php line 188</a></li> <li>at <abbr title="Symfony\Component\HttpKernel\Kernel">Kernel</abbr>->handle(<em>object</em>(<abbr title="Thelia\Core\HttpFoundation\Request">Request</abbr>)) in <a title="C:\xampp\htdocs\printdesign\web\index_dev.php line 36" ondblclick="var f=this.innerHTML;this.innerHTML=this.title;this.title=f;">index_dev.php line 36</a></li> </ol> </div> </div> </body> </html>