My understanding is the web version of Word is limited; I uploaded the file I was testing to OneDrive and opened it from there and couldnāt even see the image to copy it out.
I think this is a case of the web version of Word doing something incorrect.
EDIT: I tested it out by creating a new document in Word Online and saving it locally as well.
Opened in LibreOffice (sorry not sorry, no native Word for Linux) the available formats provided by copying the image to the clipboard are:
TIMESTAMP,TARGETS,MULTIPLE,SAVE_TARGETS,application/x-openoffice-svxb;windows_formatname="SVXB (StarView Bitmap/Animation)",application/x-openoffice-objectdescriptor-xml;windows_formatname="Star Object Descriptor (XML)";classname="8BC6B165-B1B2-4EDD-aa47-dae2ee689dd6";typename="LibreOffice 6.4 Text Document";displayname="file:///home/michael/scratch/Document1.docx";viewaspect="1";width="35033";height="27704";posx="0";posy="0",image/png,application/x-openoffice-gdimetafile;windows_formatname="GDIMetaFile",application/x-openoffice-emf;windows_formatname="Image EMF",application/x-openoffice-wmf;windows_formatname="Image WMF",application/x-openoffice-bitmap;windows_formatname="Bitmap",image/bmp,application/x-libreoffice-internal-id-109262
Whereas copying the image from Word Online gives us the available formats:
TIMESTAMP,TARGETS,SAVE_TARGETS,MULTIPLE,text/html
i.e. there is no image format available on the clipboard for us to use. If I pull the data from the clipboard in the text/html
format, I get (for a sample small image) the following:
<meta http-equiv="content-type" content="text/html; charset=utf-8"><img class="WACImage SCXW69312358 BCX0" unselectable="on" src="data:image/png;base64,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" style="margin: 1px; padding: 2px; user-select: text; -webkit-user-drag: none; -webkit-tap-highlight-color: transparent; border: none; white-space: pre !important; vertical-align: baseline; color: rgb(0, 0, 0); font-family: "Segoe UI", "Segoe UI Web", Arial, Verdana, sans-serif; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial; width: 44px; height: 29px;">\x00
which gets turned into this: