Press “Ctrl” key button and meanwhile click on it. After that, you should find “Signatures” button in the right pane.Then in the new window of ‘Outlook Options”, switch to “Mail” tab.For a start, head to “File” menu and click “Options”.Method 2: Resize by Modifying HTML File of Signature Lastly, click “OK” to save the signature.And then in “Edit signature” section, remove the original signature and paste the copied one.In the dialog of “Signature and Stationery”, you should select the source signature. Then go to “Insert” > “Signature” > “Signatures”.Press “Ctrl + A” to select all, and “Ctrl + C” to copy it. After resizing the picture to your desired size, you need to copy the changed signatures.And directly drag the picture’s edge to change its size. After the signature gets inserted into the email message body, you need to pitch on the picture.From its drop down list, select the signature whose inner picture you intend to resize. In the New Message window, switch to “Insert” tab and click on “Signature” button.I have no way but to use some other handy workarounds. However, although I’ve selected the pictures, I cannot change its size. Some of them are too small, while the others are too big. However, after adding the pictures in signature editor, I find that their sizes are not unified.

So as to make my signature more intriguing, I intend to insert several interesting pictures. Here are 2 available workarounds to accomplish it. Unfortunately, Outlook doesn’t permit you to change its size in signature editor. When you insert a picture into a signature in Outlook but find it too large, you will wish to resize it.

How to add logo to email signature in outlook 2018