Resize Logos for Web Use

I have several logos sitting in PNG that now need to be resized for online display. Their main destination is a brand-partner website, so the final files must look crisp on both desktop and mobile while keeping file sizes lean for quick loading... (Budget: $10 - $30 AUD, Jobs: Adobe Illustrator, Adobe Photoshop, Digital Art, Graphic Design, Illustrator, Image Processing, Logo Design, Photo Editing, Photoshop, Web Design)