Broken image on make a new blog page

**Describe the bug**
The image next to the file selection box doesn't display.

**To Reproduce**
Steps to reproduce the behavior:
Got to the make a blog page and scroll down.

**Expected behavior**
An image representing a file should appear.

**Desktop (please complete the following information):**
Windows 10, Chrome 95.0.4638.69, PC

**Additional context**
The current image is a hotlink from flaticon.com. It looks like FlatIcon requires attribution and disallows hotlinking.

从新建博客页面开始，检查文件选择框旁边的图像，重点关注当前的 flaticon.com 热链接。确认图像来源，并将失效的引用替换为可用的图像来源；当文件图像在页面上的 Chrome 中显示时，即表示完成。

由索引模型根据 Issue 内容生成。