No need to get your magnifying glasses out to view these artworks in high resolution - these websites have already taken care of it with ultra high-resolution imagery, "infinitely zoom-able" artworks and large-scale works of art.
Google Art Project -
Launched in 2011, the Google Art Project takes visitors on a virtual tour of some of the most famous art collections in the world. Users can view masterpieces in incredible detail, zooming in to the finest brushstroke thanks to extremely high resolution imagery.
Museum of Neverending Art - http://www.museumofneverendingart.com/hall-of-fame.html
This interactive online website is a never-ending gallery of user-submitted artworks. Pick a pixel on the website and zoom in to see it enlarged into an image, photo or artwork.
Juan Francisco Casas - http://www.juanfranciscocasas.com/
His images might look like blue-tinged photographs, but the large-scale works of Juan Francisco Casas are hand-drawn with a blue pen in spectacular detail.
The Picture of Everything - http://www.thepictureofeverything.com/
The Picture of Everything is an artwork that was first started in 1997 when artist Howard Hallis began drawing Spider-Man. It has since evolved into a complex image of as many super heroes, cartoon characters, rock stars and religious figures as Hallis could think of. The work was completed in 2010.
Zoom Quilt - http://zoomquilt2.madmindworx.com/
Zoom in on this seemingly infinite artwork of cartoons and fantasy worlds as one world morphs into another.
80-gigapixel panoramic photo of London - http://www.360cities.net/london-photo-en.html
This panoramic image of London is comprised of 7,886 individual photographs, enabling viewers to zoom in and out on tiny details across the city.