Static image src in Vue.js template

My Vue component contains some images. I want to do lazy-loading later, so I need to set the src of the images to a small image, first.

<template>
        <div v-for="item in portfolioItems">
            <a href="#{{ item.id }}">
                <img
                    data-original="{{ item.img }}"
                    v-bind:src="/static/img/clear.gif"
                    class="lazy" alt="">
            </a>
        </div>
</template>

Gives me a bunch of errors, like:

[Vue warn]: Invalid expression. Generated function body: /scope.static/scope.img/scope.clear.gif vue.common.js:1014[Vue

[Vue warn]: Error when evaluating expression "/static/img/clear.gif": TypeError: Cannot read property 'call' of undefined (found in component: )

webpack.config.js:
module.exports = {
    // ...
    build: {
        assetsPublicPath: '/',
        assetsSubDirectory: 'static'
    }
}