Add alt attribute to most used img tags

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/document_states/widgets.py

@@ -17,8 +17,8 @@ def widget_transition_events(transition):
 
 def widget_workflow_diagram(workflow):
     return mark_safe(
-        '<img class="img-responsive" src="{}" style="margin:auto;">'.format(
-            reverse(
+        '<img alt="{}" class="img-responsive" src="{}" style="margin:auto;">'.format(
+            _('Workflow preview'), reverse(
                 viewname='document_states:workflow_image', kwargs={
                     'pk': workflow.pk
                 }

mayan/apps/documents/templates/documents/document_print.html

@@ -1,5 +1,7 @@
 {% extends 'appearance/base_plain.html' %}
 
+{% load i18n %}
+
 {% load documents_tags %}
 
 {% block title %}{{ title }}{% endblock title %}
@@ -7,6 +9,7 @@
 {% block content_plain %}
     {% for page in pages %}
         <img
+            alt="{% trans 'Document page image preview' %}"
             src="{% get_api_image_url page width=width height=height %}" style="width: 100%;"
         />
     {% endfor %}

mayan/apps/documents/templates/documents/forms/widgets/document_page_image.html

@@ -1,3 +1,5 @@
+{% load i18n %}
+
 {% load appearance_tags %}
 {% load documents_tags %}
 
@@ -8,6 +10,7 @@
         {% get_icon 'mayan.apps.documents.icons.icon_document_image_loading'  %}
     </span>
     <img
+        alt="{% trans 'Document image' %}"
         class="thin_border {{ image_classes }}"
         data-url="{% get_api_image_url instance width=image_width height=image_height zoom=image_zoom rotation=image_rotation %}"
         src="#"