I noticed a couple of potential issues:

1. Make sure the HTML input field name matches the parameter name in the controller method:

   • In your HTML view, the input field is named "image": .
   • However, in your controller method, you are trying to retrieve the file using kw.get('file'). It should be kw.get('image') to match the input field name.

2. Use the correct method to read the uploaded file:

   • In your controller method, you are using kw.get('image').filename to get the file name, which suggests that you are using Flask-like request objects.
   • In Odoo, to read the uploaded file, you should use request.httprequest.files['image'] instead of kw.get('image'). This will give you access to the file object, which you can then read and encode.

try this way:
input type="file" name="image" class="file" multiple="true" data-show-upload="true" data-show-caption="true" lass="file" data-show-preview="true" />

import base64
@http.route('/create/application', type="http", auth="public", website=True)
def create_student(self, **kw):
file = kw.get('image')
img_attachment = file.read()
request.env['op.admission'].sudo().create({
'image':base64.b64encode(img_attachment),
})

# Add any further processing or redirection logic as needed
# ...