function testOpImage(browser, opName, filename, args=[]) {
    browser.perform(function() {
        console.log(`Current test: ${opName}`);
    });
    utils.loadRecipe(browser, opName, "", args);
    utils.uploadFile(browser, filename);
    browser.waitForElementVisible("#stale-indicator", 5000);
    utils.bake(browser);

    browser
        .waitForElementVisible("#output-html img")
        .expect.element("#output-html img").to.have.css("width").which.matches(/^[^0]\d*px/);
}
@function
Clears the current recipe and tests a new Image-based operation.

@param {Browser} browser - Nightwatch client
@param {string|Array<string>} opName - name of operation to be tested array for multiple ops
@param {string} filename - filename of image file from samples directory
@param {Array<string>|Array<Array<string>>} [args=[]] - arguments, nested if multiple ops