Not really. It isn't that simple, which you'd know if you read only a few comments here. For example, my mother has only one friend with an iPhone. Of all her friends, she is the only one she cannot send images to directly. Her friends iPhone refuses and sends back an "image too large" SMS error message. The only way to get the iPhone to accept the image is to first reduce it in size via an app. Huawei, OnePlus, Samsung, Nokia - they all send and receive just fine (most on the same provider as the iPhone) but if the same image is sent from the iPhone the problem disappears, unless you try to send it back, then the error message reappears.
Then there's all the iMessage versus SMS/MMS/RCS green/blue issues. Read the comments. Apple is using lots of small dirty tricks.
I have sent many a images on an iphone via sms when imessage lacks any connectivity so this is a little weird for me to read. Maybe my OS version automatically sizes these images for sms.
