Databases are an utterly wonderful thing - and, to my neverending delight, there are more and more of them available on the Internet.

On this page, I'm listing the many image, object, and museum databases that I have come across during the years. I hope you will find them helpful.

Some of the databases offer their content under a Creative Commons license or even as Public Domain, meaning that their images are free to use (at least for non-commercial purposes). Good netiquette (and sometimes the licensing terms as well) demand that you give the source of the image; usually the databases provide a permalink to the image, which should be cited together with the database or museum or library name.

Here's my list of image and object or museum databases, in no particular order:

REALonline is mainly a database for artwork, with some objects thrown in for good measure. The site is available in both German and English.

Search the collections at the V&A London, which will yield images of objects. 

Both texts and images from a number of German museums and libraries can be found via the Deutsche Digitale Bibliothek. 

KiK-IRPA in Brussels, the Belgian Royal Institute for art, has a search engine called Balat. It will search image contents, but is best used with Dutch or French terms on the appropriate pages - at least my impression is that the English terms are patchy at best.

The online collections database of the National Museums Scotland. 

The Portable Antiquities Scheme offers a database under finds.org.uk/database listing finds made by metal detectorists, mudlarkers and other finders. 

Genevra Kornbluth has a photo archive about "luxury arts" online, including many museum objects dating back to the Middle Ages.

Metropolitan Museum: Here is the starting page for image and data resources, 375,000 images of public domain works to share, remix, or use in any way you want to, under a Creative Commons Zero license. 

Arachne is an object database for objects of the Deutsches Archäologisches Institut (DAI) and the Archäologisches Institut der Universität zu Köln. There's predominantly really old stuff - we're talking Antiquity here, so Greek and Roman things prevail.

Bavarikon is a portal with an object database, though it also includes exhibitions and information about places and important architecture.

Europeana is an art and object database that searches collections from various places in Europe. It's available in several different languages, and thus it's possibly worth it to try searching in more than one language for what you are looking for. Not so cool: There's a possibility to use some filters, but I haven't found a filter for the date yet, so you will get all kinds of things from all times.

The Fitzwilliam Museum in Cambridge has an online Explorer where you can search the collections. Their online exhibitions are also worth a look! 

archREAL is an object database with archaeological small finds; unfortunately this project sort of petered out, and has lain dormant since about 2004. If you want to use the database, you have to ask for a login (due to copyright reasons). It's only available in German.

Here is an alternative gateway to browse images from the Bodleian Library. There's a thumbnail overview for each of the individual manuscripts, and the mss themselves are sorted by century and area of origin. The pics seem to be in the main database as well.

The bibliothèque numérique de Lyon has a large number of miniatures from manuscripts of the 5th to 16th century. 

The Research Center for Medieval Nubia has an online textiles database. There's also an interesting article about textile analysis on the page, in case you're not familiar with this and would like to read an introduction.

Not a real database, but the Rode Project features two altars by the late-medieval artist Hermen Rode. One of them is in Lübeck, the other in Tallinn, and you can have a really close look at them in the Rode Project.

A large collection of images is the Digital Imaging Project with art and architecture (mostly architecture) from North America and Europe, from prehistoric to modern times.

The Database Machine Drawings is exactly that - you can search for machine drawings from 1235 to 1650. 

Theoretically an image/object database, but the search function does not work for me, is the Kult.Doku database. (Probably the php scripts are outdated, as the site is from 2003). It collects treasures shown in Austrian Landesausstellungen (big national exhibitions) in a database, with information taken from the exhibition catalogues. You can browse the catalogue entries, though - "Ausstellungen" gets you to a map of Austria, where you can select a federal state. That gets you a list of all the exhibitions there, some of which have their data online and if you click these links, you get the list of objects. A little awkward, but a nice way of getting an overview on things.

Mandragore searches images from manuscripts in the Bibliotheque Nationale de France, provided you know the French word for what you are looking for. You will see a thumbnail and can see a slightly larger image as well, but the ones I took a closer look at were usually too small and/or too low in resolution to make out details properly. There is a remedy for that, though, at least in some cases - armed with the knowledge of what image you want to see, from what manuscript and on which folio, heed over to Gallica, the search engine for the BNF, and search there for the manuscript to enjoy the digitised page in very good resolution. You can also use Gallica to search for other images and books.

Here you can browse Medieval and Renaissance Manuscripts from the Bodleian.

The Bildindex für Kunst und Architektur, a German-language database that lets you search in the Marburger Bildarchiv (well-known to architects) as well as the image archives of a lot of museums, institutes for heritage conservation and universities. 

Free1000s has selected artwork from the Middle Ages and more modern times. It has no really good search function, but is nice for a bit of a browse, and there's not too much to browse through if you are looking for medieval art. There's also a link to a newer version of the site, which has different pictures from this one.

Another good database is the Rijksstudio, the image database of the National Museum of the Netherlands. You can even search in English, though using Dutch search terms might be the better choice - as usual.

A collection of stained glass from Britain is available at the Corpus Vitrearum Medii Aevi website.

Not searchable with freetext search words, but with several different topics to help you browse and discover: the website with images from Medieval Wall Paintings in England.