If you are planning to send a campaign with no image and just short text and no emojis, you can use the SMS format. The character limit for this message is a max of 160 characters. If you add emojis to the text the character limit should be below 70 characters.
If you plan to add an image or longer text blocks you should use MMS format, so that the message doesn’t get split unexpectedly.
When sending an MMS campaign the character limit of the text is 1600 characters, but it’s still ideal to aim for around 160 characters as best practice.
If using an image in .jpg format, the file size should be no bigger than 300kb, but if needed, the size can go up to 500kb. On phones, a portrait or tall images look the best with an aspect ratio of 9:16. We can do a square as well. We do support .png and gif in addition.
If using a gif image, we have seen that 400X400 works best across most mobile devices, and to keep the size under 500kb. It’s better to get as close to square as possible, to avoid unexpected compression or distortion by carriers. For example, on certain iPhones we have seen an issue with gif images getting oddly resized.