Mail.app in 10.6.4 pastes screenshots as TIFF

PNG all the way. No tiff in sight. Not sure what your computer was smoking, but something tells me you've been shooting tiff all along and never noticed it.

Been PNG for quite a while and that would have been caught long ago by me or one of the many other users and reported as a BUG. Tiff file size can get out of hand, especially if not lzw compressed.

This really helped me. I have had a problem copying screen grabs etc in to Evernote from my Macbook Pro and could not work out the reason. Now changed to jpg and problem is resolved.

Thanks.

You can use the "file" utility (/usr/bin/file) from the terminal to identify the true file type, regardless of file name extension. It looks at the first few bytes of the file and checks it against a database of known file format patterns.

For those of you who don't know how to use /Applications/Utilities/Terminal.app, just type "file", then a space, then drag the file you're attempting to identify to the terminal window. That will insert the path to the file. Then just hit enter.

And if you have the developer tools installed, check out /Developer/Applications/Utilities/Clipboard Viewer.app - after taking the screenshot, hit the reload button. It will show you which types of data were placed on the clipboard. More than one type may be present, and each application gets to decide what pieces of the clipboard it will use upon paste. That may account for some of the discrepancies you're seeing.

Note that JPEG is not a great format for taking screen shots, especially of full windows, which includes the translucent shadow of the window and transparency of the rounded corners.

JPEG does not support an alpha channel, so the screen shot will not have the proper transparency.

10.6.4 here.

My defaults read command returned "JPG".

Pasting it into Mail, sending the message, and opening it in Mail (I sent the file to myself using the same email account) show the message's attachment with a ".tiff" extension.

Going to Preview, choosing File > New from Clipboard and then saving, the file auto-chosen type is PNG. Since I rarely use Preview to save files, this may be a default option, not an indicator of actual file type...or not.

Saving the attachment file from Mail put a file called "PastedGraphic-1.tiff" on my desktop. File > Get Info claimed the file Kind was a "TIFF image". The file's icon showed the contents of the capture.

Without doing anything else, I changed the file name extension to .jpg, so now the name read "PastedGraphic-1.jpg". The icon retained the capture image. Doing Get Info now reported the file as "JPEG image".

This tells me that Get Info does not really know what the format is either and is just using the filename extension for the file's type, though Preview must be pretty good at guessing formats in order to display the file as an image.

Opening the file with BBedit shows a bunch of binary code characters. Typically for me, opening both JPEGs and TIFFs in a text editor usually reveals some human-readable references to the actual file type and creating application (yes, I do this for work quite often). This particular file had nothing like that at all as far as I could find.

Hard to say definitively what the file type actually is from my tests. Maybe someone that knows more about file formats can chime in?

OS 10.6.4
Default png
Mail png
Preview png

I tried this in 10.6.4 and it pasted at PNG.

Just did the tests...PNG all the way, Preview and Mail

10.6.4

I must be the oddball...my screenshots came up as BMP, WTF? I certainly never caused that to happen!

I've changed to PNG, but haven't done the paste test yet.

OS X 10.6.4

defaults read com.apple.screencapture type PNG