[Django]-How to show only one image in Django admin inline

extra = 0

class GalleryImageInline(admin.TabularInline):
    """
    Gallery Image inline
    """
    fieldsets = (
        (
            None, 
            {
                'fields': ('name', 'image',)
            }
        ),
    )

    model = Image
    extra = 0


class GalleryAdmin(admin.ModelAdmin):
    """
    Case Study Admin
    """
    fieldsets = (
        (
            None, 
            {
                'fields': ('location', 'date',)
            }
        ),
    )

    inlines = (GalleryImageInline, )
    list_display = ['location', 'date']
    list_filter = ['location', ]

And in my opinion, for a inline that has images to be useful you need to actually display the image inline (so custom override the image widget):

from django.contrib.admin.widgets import AdminFileWidget
from django.utils.translation import ugettext as _
from django.utils.safestring import mark_safe
import os
import Image

class AdminImageWidget(AdminFileWidget):
    def render(self, name, value, attrs=None):
        output = []
        if value and getattr(value, "url", None):

            image_url = value.url
            file_name=str(value)

            # defining the size
            size='100x100'
            x, y = [int(x) for x in size.split('x')]
            try :
                # defining the filename and the miniature filename
                filehead, filetail  = os.path.split(value.path)
                basename, format    = os.path.splitext(filetail)
                miniature           = basename + '_' + size + format
                filename            = value.path
                miniature_filename  = os.path.join(filehead, miniature)
                filehead, filetail  = os.path.split(value.url)
                miniature_url       = filehead + '/' + miniature

                # make sure that the thumbnail is a version of the current original sized image
                if os.path.exists(miniature_filename) and os.path.getmtime(filename) > os.path.getmtime(miniature_filename):
                    os.unlink(miniature_filename)

                # if the image wasn't already resized, resize it
                if not os.path.exists(miniature_filename):
                    image = Image.open(filename)
                    image.thumbnail([x, y], Image.ANTIALIAS)
                    try:
                        image.save(miniature_filename, image.format, quality=100, optimize=1)
                    except:
                        image.save(miniature_filename, image.format, quality=100)

                output.append(u' <div><a href="%s" target="_blank"><img src="%s" alt="%s" /></a></div> %s ' % \
                (miniature_url, miniature_url, miniature_filename, _('Change:')))
            except:
                pass
        output.append(super(AdminFileWidget, self).render(name, value, attrs))
        return mark_safe(u''.join(output))

Note: that this does some resizey stuff you may not like – so you may need to rewrite the thumb sizing part of the widget yourself.

so then you are going to need to override the widget in your inline’s form:

class GalleryImageForm(forms.ModelForm):
    """
    Image Admin Form
    """
    class Meta:
        model = Image
        widgets = {
            'image' : AdminImageWidget,
        }

class GalleryImageInline(admin.TabularInline):
    ...
    form = GalleryImageForm
    ...

and you end up with somethig like this (this is part of another project and has a bunch of extra stuff):

In case if you use sorl-thumbnails , widget is like this:

from django.contrib.admin.widgets import AdminFileWidget
from django.utils.safestring import mark_safe
from sorl import thumbnail


class AdminImageWidget(AdminFileWidget):
    def render(self, name, value, attrs=None):
        output = []
        if value and getattr(value, "url", None):
            t = thumbnail.get_thumbnail(value,'100x100')
            output.append('<img src="{}">'.format(t.url))
        output.append(super(AdminFileWidget, self).render(name, value, attrs))
        return mark_safe(u''.join(output))


class GalleryImageForm(forms.ModelForm):
    """
    Image Admin Form
    """
    class Meta:
        model = Image
        widgets = {
            'image' : AdminImageWidget,
        }

class GalleryImageInline(admin.TabularInline):
    ...
    form = GalleryImageForm
    ...