All image projects have input and output. Considering what you are starting with, such as an exported image, shapes with text, or a picture from a camera, is just as important as determining your end product, which may be a figure that meets journal requirements, a visual for a presentation, or an image for social media.
Image projects may use one or more software for image editing. Workflows in Photoshop and Illustrator are usually implemented when other imaging programs lack the granularity needed to complete a function. The image type needed for input or output can also determine which programs are used. Image type can be the overall structure (raster or vector), or the file type such as .JPG or .PDF.
Photoshop is the primary program for editing raster images.
Raster images are based on pixels. A pixel represents one dot or square of a color.
Raster images have a width and height (dimensions). Dimensions are measured in pixels and in inches/centimeters.
The resolution of an image is determined by how dense the pixels are for the dimensions of the image. This measurement is often seen as DPI or PPI. A "hi-res" image refers to an image that has a high resolution.
Common Raster file types:
If a software program or website allows you to insert an image, raster image file types are very commonly accepted.
Illustrator is the primary program for editing vector images.
Vector images are based on computer-generated lines.
Vector images are not based on dimensions.
Color and outline properties are applied to vector shapes. Vector shapes and text are combined to create an illustration or image that is vector-based.
Common Vector file types:
Vector image file types are less commonly accepted into software programs or websites that allow you to insert an image.
PDFs can be created as vector files or raster files. Some PDFs have both vector and raster elements.
A PDF in which you can search for text, or highlight a word, uses vector text elements.