If you don't mind getting 'under the hood', the shell has a file command that can help identify a wide variety of files.
Open /Applications/Utilities/Terminal
In the window that opens, type:
file
followed by a space (the space is important)
Then drag the file in question from the Finder into this Terminal window, then press return.
file will examine the file and attempt to identify it and give a little info:
% file ./Proposal\ copy.pdf
./Proposal\ copy.pdf: PDF document, version 1.6 (zip deflate encoded)
% file ./download.gif
./download.gif: GIF image data, version 89a, 480 x 370
If you want to get even more detail, replace file with mdls:
% mdls ./download.gif
_kMDItemDisplayNameWithExtensions = "download.gif"
_kMDItemPhotoEmbedding = (
{
"vec_data" = {length = 1024, bytes = 0x79aa82ad 99a1ed2c 0798fa1c e52adfa8 ... 11ab291d cb1deda8 };
"vec_dim" = 1;
"vec_format" = 1;
"vec_id" = 5037;
"vec_version" = 5;
}
)
kMDItemBitsPerSample = 32
kMDItemColorSpace = "RGB"
kMDItemContentCreationDate = 2025-04-01 19:04:47 +0000
kMDItemContentCreationDate_Ranking = 2025-04-01 00:00:00 +0000
kMDItemContentModificationDate = 2025-04-01 19:04:47 +0000
kMDItemContentRating = 0
kMDItemContentType = "com.compuserve.gif"
kMDItemContentTypeTree = (
"com.compuserve.gif",
"public.image",
"public.data",
"public.item",
"public.content"
)
kMDItemDateAdded = 2025-04-01 22:07:10 +0000
kMDItemDisplayName = "download.gif"
kMDItemDocumentIdentifier = 0
kMDItemEmbeddingVersion = 3
kMDItemFSContentChangeDate = 2025-04-01 19:04:47 +0000
kMDItemFSCreationDate = 2025-04-01 19:04:47 +0000
kMDItemFSCreatorCode = ""
kMDItemFSFinderFlags = 0
kMDItemFSHasCustomIcon = (null)
kMDItemFSInvisible = 0
kMDItemFSIsExtensionHidden = 0
kMDItemFSIsStationery = (null)
kMDItemFSLabel = 0
kMDItemFSName = "download.gif"
kMDItemFSNodeCount = (null)
kMDItemFSOwnerGroupID = 20
kMDItemFSOwnerUserID = 501
kMDItemFSSize = 506200
kMDItemFSTypeCode = ""
kMDItemHasAlphaChannel = 1
kMDItemInterestingDate_Ranking = 2025-04-01 00:00:00 +0000
kMDItemKind = "GIF image"
kMDItemLogicalSize = 506200
kMDItemOrientation = 0
kMDItemPhotosSceneClassificationMediaTypes = (null)
kMDItemPhotosSceneClassificationTypedIdentifiers = (
"1-492"
)
kMDItemPhotosSceneClassificationTypes = (null)
kMDItemPhysicalSize = 507904
kMDItemPixelCount = 177600
kMDItemPixelHeight = 370
kMDItemPixelWidth = 480
kMDItemProfileName = "sRGB IEC61966-2.1"
kMDItemWhereFroms = (
"blob:https://giphy.com/3ec89451-6c10-4e3f-f9ec-e3c0f908a974"
)
