django admin后台无法显示图片

请教下各个大牛, 怎我上传的图片在admin显示不出来呢 ?

谢谢呀

models.py

class Image(models.Model):
    Phase = models.ForeignKey(Growth_phase,on_delete=True)
    pic = models.ImageField(u'图片',upload_to='image') 
    comments = models.CharField(max_length=30,blank=True)
    date_upload = models.DateTimeField(auto_now_add=True)

admin.py

from django.contrib import admin

# Register your models here.
from app_aman_growth.models import Growth_phase,Image
from django.utils.safestring import mark_safe

admin.site.register(Growth_phase)
@admin.register(Image)
class ImageAdmin(admin.ModelAdmin):
    list_display = ('Phase','comments','pic')
    readonly_fields = ('pic',)

    def image_data(self):
        return mark_safe(u'<img src="%s" width="100px" />'.format(self.pic.url))
    image_data.short_description = u'图片'

setting.py

MEDIA_ROOT = r'D:\Program Files\Python3.7.2\Aman'
MEDIA_URL = '/images/'