Depends on the quality of the picture and how much you enlarge it. When you enlarge it too much, you will see the pixels, which is never a good thing.
You could make an image, and then print it out onto blank ironing paper, and then iron it on to a shirt. You can also save your design to send to a commercial printer but remember when you do to save it as CMYK. This is often needed to break the design down into its base colors. Additionally, if you are wanting the printer to enlarge the design you should save it at its highest resolution. 300 dpi is generally accepted as print quality. If a design was a small jpeg, for example, it will not enlarge well. Whereas, a vector-based graphics (.eps or .ai) that is not broken down into individual pixels will enlarge without problem.
To blow up old photos and make them larger and more detailed, you can use a scanner to digitize the photo at a high resolution. Then, you can use photo editing software like Photoshop to enlarge the image without losing quality. Additionally, you can take the digitized photo to a professional printing service that specializes in enlarging photos.
When you enlarge the image, you can see alot of the pixels depending on the pixel count or resolution of the image. There is a definite pixel count that will not change when the image is enlarged or shrank so the pixels either squish together or become to large that they change the resolution and quality of the image.
To convert a JPG image to high resolution, you can use image editing software like Adobe Photoshop or online tools like Pixlr. Open the JPG image in the software, then go to the image settings or resize options to increase the resolution. Keep in mind that increasing resolution may result in some loss of quality, so it's best to start with a high-quality image if possible.
You can enlarge image in Image Size dialog in Photoshop, Image > Image Size. At top of window you will see current/new size in bytes. When you enlarging images be aware because you can loose quality.
It all depends on the project. Raster images are resolution dependent, you loose quality if you enlarge the image. Vector graphics maintain image quality when enlarged and are best suited for logos, or any design that will be reproduced in different sizes.
Adobe
No, only on the quality. If you have a picture that is in low quality, perhaps because you scanned it that way, printing in high resolution won't be able to improve the image quality.
Yes it is, depend of what You want to do with image. IF You want to print then resolution is very important, if You gonna post image on web site more important are pixel dimensions because on web images will be displayed with 72 ppi regardless of original image resolution.
If you play a 4K resolution video on a 1080p monitor, the video will be downscaled to fit the lower resolution of the monitor. This may result in a decrease in image quality and clarity compared to watching the video on a 4K monitor.
Its not possible to save image while you are zooming it,you can try to enlarge it and then save it but its not recommended because loss of quality(when you enlarging photo)