"The Art of the Mughals after 1600," an interpretive site at the Metropolitan Museum: [site]

MANY MUGHAL SITES, with discussion (the tomb of Itimad ud-Daulah, the Red Fort, the Taj Mahal, Humayun's Tomb, Fatahpur Sikri, the Jama Masjid, Akbar's tomb); also many RAJPUT PALACES and other sites: art-and-archaeology [site]. 

Havell, E. B., A Handbook to Agra and the Taj, Sikandra, Fatehpur-Sikri, and the Neighbourhood (1904): [on this site]

ANU ARCHITECTURAL IMAGES (HUGE!)
DELHI
=Humayun's Tomb complex: [site]
=Museums: [site]
=Purana Qila: [site]
=Qila-e Kuhna mosque: [site]
=Safdarjang's tomb: [site]
=Shahjahanabad: [site]
AGRA
=Agra Fort: [site]
=Fatahpur Sikri: [site]
=Itimad ud-Daulah's tomb: [site]
=Sikandra: [site]
=Taj Mahal: [site]

From Jahangir's and Shah Jahan's time, from the Berger Collection:
    =Sikandra (near Agra): Akbar's tomb (1613), started by Akbar but then redesigned by Jahangir: [one set]; also DSAL images, 1945: [site]; also ArchNet: [site]
    =Agra: Itimad ud-Daulah's tomb (1628), built by Jahangir's wife Nur Jahan for her father; in two sections: [two sets]
    =Agra: Taj Mahal, supreme Mughal monument; built by Shah Jahan for his wife Mumtaz Mahal (d.1631), in three sections: [three sets]
    =Agra: Agra Fort; begun by Akbar in 1865, and including Shah Jahan's famous marble Moti Masjid, or "Pearl Mosque":  in four sections: [four sets]
    =Delhi: "Fort Rouge," in two sections: [two sets]

From Aurangzeb's time, from the Berger collection:
=Aurangabad: Bibi ka Maqbara, the tomb built by Aurangzeb for his queen Dilras Bano Begam, who died in childbirth in 1657; many images in section 1 (page 2): [one set] 

More excellent Agra images from "Phil G.": [site]

From Jahangir's and Shah Jahan's time-- DSAL images:
=Agra: Itimad ud-Daulah's tomb: [site]
=Agra: Taj Mahal: [site]

=Lahore: many good architectural images: [site]

=Archnet Digital Library architectural images, 1600's-- many sets: [site]

Paintings with ZOOM capabilities (FAMSF):
=Bikaner Mughal style, c.1600-1620: *"Blue Roller Bird"*
=Benares Mughal style, early 1600's: *"Rama and Balarama with their Monkey and Bear Allies"*
=Mughal style, early 1600's: *"Marine Scene"*
=Jain style, c.1625: *"Marudevi tells her Fourteen Auspicious Dreams..."*
=Mughal style, c.1625-1650: *"Two Royal Antelopes"*
=Mughal style, 1600's: *"Holy Man Holding a Vina"*
=Kashmir Mughal style, 1600's: *"Celebration of Holi"*
=Malwa style, 1634: *"Maidservant in Conversation with her Mistress"*
=Mughal style, c. late 1600's: *"Marine Scene of Battle"*
=Mughal style, c. 1600's: *"Portrait of a Raja"*
=Mughal, c.1670: *"Nawab General Firoz Khan of Golconda"*
=Bundi style, c.1685: *"Holy Man in Meditation"*
=c.1690: *"Portrait of Fakir Khan and his Sons"*
=Deccani, c.1700: *"Raja Bikram and the Angel"*
=Malusa, c.1700: *"The Adoration of Krishna"*

=Shah Jahan's excellent "Padshah Namah" album of paintings, Univ. of Penn.: [site]

=The Princeton Shahnamah Project, wonderful Persian manuscripts presented very elegantly and with much background material: [site]

Hand-knotted rugs
    =Mughal carpets at the Met-- a gorgeous presentation and study: [site]
    ="Symmetry and pattern: the art of Oriental Carpets": [site]
    ="Oriental Rugs" at islamicart.com: [site]

=Islamic art at the Met--  highlights of the collection, many Indo-Muslim, limited but helpful ZOOM capabilities: [site]

="The Black Peacock," a website displaying many medieval and other paintings, with critical commentary, in a Gauriya Vaishnava perspective: [site]