ShortPixel WP Image Optimiser
This great little plugin will automatically compress any images you upload to your WordPress website. While personally I recommend you optimise images before you upload them, sometime this isn’t always practical: when you upload directly from your phone, for example. For times like those, this plugin will automatically scale and compress your image file so it loads faster when someone visits your site. Google loves fast website and for that you need images of a sensible size.
You can compress up to 100 images per month on the free plan. If you need more you can opt for a monthly subscription or buy a block of one-off credits. Great value!