It is. But it doesn't have to be.
Here is some information that we have found to give good results:
By default, the native iPhone Mail app embeds the images in the body of the email and reduces image size for smaller bandwidth usage and greater deliverability.
When you select the image file(s) to attach, choose to send “full-size." This sends the image as an attachment instead of embedded image. [NOTE: You may see a warning that the file might be too large with the option to try anyway or send via a link, which segues perfectly into Option 2.]
To send original quality images from your Apple device, the most reliable method is to log into your iCloud account choose the photo(s) and share a link. We can download the original resolution file (at which it was saved) without having any other editor rights.
[This is only a problem when your images are not backed up. ]
[If you never backup your phone, go make an appointment at the Apple Store immediately and learn how to do it and why it's important.]
Alternately, if you use any email app other than native iPhone Mail, image files should attach and send perfectly (within app file size allowances [Gmail and Yahoo both limit attachments to 25mb]).
Please note that ANY image saved from a social media site, via a screenshot, or right-clicked-and-saved from a website will NOT be sufficient to reproduce.
All website images are 72 DPI. Print images need to be at least 300 DPI.
See more about that in Raster Images below.
What is a Raster Image?
Raster images are made up of dots of color. How close the dots are placed next to each other is measured in Dots Per Inch (or DPI). When an image is stretched to enlarge, more dots cannot be created– they just stretch and are more visually apparent. The edges of things look jagged and may be referred to as “pixelated.” Photographs are always raster files.
Common raster file types are JPG, PNG, GIF, and TIF.
What is a Vector Image?
Vector images are lines plotted on a graph and can be enlarged infinitely. When logos are created as a vector file, they often also contain Pantone or CMYK process colors that will reproduce the colors with high accuracy.
Common vector file types are EPS, AI, and SVG. PDF files can be vector but MUST be saved from the native vector file to be vector themselves.