Fix Invalid DOM property and manifest error

**Describe the bug**
Errors like below should be fixed:
```
Warning: Invalid DOM property `class`. Did you mean `className`?
    at img
    at div
    at div
    at Gallery (http://localhost:3000/static/js/main.chunk.js:1632:86)
    at div
    at Home
```

```
Manifest: Line: 1, column: 1, Syntax error.
```

**To Reproduce**
1. start project
2. open console