The 'transparent' tool is missing from the image view - what can i do?

I have not seen this tool in Preview since upgrading to Sierra.

Try the "Instant Alpha" tool instead - the second one from the left. Click somewhere into the area you want to make transparent, then click "Instant Alpha", then use the command "Edit > Delete" and the area will become transparent.

1 - this is the Photos for Mac forum - that is a screen shot from Preview for Mac not Photos for Mac

2 - it is exactly the same as I have using Preview to edit a PNG image or a JPEG image so I assume you are mis-remmebering about the transparency tool or maybe it is only available for other than JPEGs and PNGs - If you post in the the correct forum would give you a better chance of getting better help - I will request the hosts to move it to a better forum

LN

You're welcome 🙂