Upload all the images for your portfolio / gallery in one go.
You can find the bulk upload function in Portfolio → Bulk Upload.
Using this tool you can upload multiple portfolio images at once. First, select if you want the portfolio items to be a Draft or Published. Click the Choose Files button to add files from your computer, and use Ctrl+Click or Shift+Click to select multiple files. When the images have been uploaded you can set the title, content and categories. Click the Save Items button at the bottom of the page to save the data. You can edit individual items by going to Portfolio → All Items on the WordPress menu.
We recommend that uploaded portfolio images are at least 1024px wide, so that the images will fit neatly into most column layouts and on devices. React will not scale up images, so the larger the original image the better it will look when fit into the theme. If the original image is larger than 1920px in any direction we recommend resizing it to 1920px on the largest side before uploading or it may be too large for the the thumbnail script to resize, especially if your server memory limit is low.
We highly recommend organizing images into categories when possible. It will come in handy when you come to display the images on a page / post.
Visit the Setting up a portfolio section