[Bug Report] 1.7.x progressive image require not working properly

[AllanChain]

Code Example

require(`@/assets/${url}?vuetify-preload`)

Expected

Upgrade from 1.6.0 without change

Actual

Problem 1: dynamic required image

Invalid prop: type check failed for prop "src". Expected String, Object, got Module 

I have to add .default for dynamic required image.

Problem 2: generated image incorrect

The src changed from data url to something like /292f0ef4743f73e3f8b2ed3f9306ea61.jpg, which looks like module.exports = "data:image/jpeg;base64,/9j/4AA, so that the browser can't display the image properly, just stuck at low-res placeholders.

[AllanChain]

Reproduce: https://github.com/AllanChain/vuetify-loader-bug-169