Sufficient enough for what? You can sort this out yourself without step-by-step instructions.
Anywhere you have inline styles - style=" ... " you can move those rules to a <style></style> section in the head of your page. Remember that you might need to add classes so that you can target the correct element(s).
You may not have to specify the width and height attributes, but IMHO, it is best to do so. They are not so much style as they are dimensions that allow a browser to reserve the area while it paints the page.
If an error occurs while trying to load or render the image, and an onerror event handler has been configured to handle the error event, that event handler will get called. This can happen in a number of situations, including: ..... The specified image's metadata is corrupted in such a way that it's impossible to retrieve its dimensions, and no dimensions were specified in the element's attributes.