Download package then unzip, you will have a component and a plugin.
You can install component as normal.
How to install JMS Multi Images Upload for Virtuemart System Plugin: You can read here
How to use JMS Multi Images Upload for Virtuemart System Plugin:
For a new product, you have to save it before use plugin
Edit a product, then go to Product images tab, you will see "Select files" button at the bottom. Click on bottom, then choose images from your desktop, plugin will automatically upload those images, create thumbnails for them and update those images for product by ajax.
Note: on some server, when you upload more 5 images, some images don't upload, some images upload 2-3 times, please check :
1. limited size for uploading of your size, maybe it is 2Mb and size of your images are big
2. your images have captial extension like .JPG instead of .jpg, please download latest version of my plugin
3. When some images upload 2-3 times, please go to plugins\system\jmsmultiupload\assets\js folder, edit multiupload.js file, find line 43 "url: url,", add 1 line below it "singleFileUploads:false,"