InDesign Best Practices 1: Graphic Formats

This thread (and others I will start with a topic header starting with InDesign Best Practices) is due to a bit of altruism and a lot of selfishness. (Yes, if you search for "best practices" there are some useful threads but not nearly enough.) The Adobe documentation for InDesign doesn't say much about best practices for advanced and even many basic tasks. There are tutorials out there outside this forum and the Adobe helpfiles. But, I find that this forum and questions and the answers from very-helpful expert folks on it are generally better than those tutorials. I have learned a lot from those experts over the years. One of my main roles in life over the past couple of decades seems to be pushing InDesign to the limits (and often beyond, as in when, with an early 19.x version, I couldn't edit many of my files in InDesign for several months). And, I have been paying attention to what the experts said. So I am going to post my hard-won knowledge by topic with "InDesign Best Practices" in the header so that it's easier for me and others to find them. Now, on to graphic formats. I am certain that some exeperts will trash my recommendations, but that's why this is a thread with replies!

InDesign best practice question: Which format should you use for graphics that you link into an InDesign document and why?

• Small InDesign document, photograph that you need to tweak in Photoshop, but without adding transparency: link to your tweaked Photoshop .psd file. Why? Because
  • For a small document, the performance hit of a .psd file is negligible.
  • You should link so that, if you look at the photo in context, you can right-click it and select "Edit Original" and it pops up in Photoshop so that you can tweak it. You can leave it open in Photoshop and keep tweaking and then refreshing (in InDesign, click the yellow triangle at the top left of the photo's frame) until it looks right.
• Large InDesign document, photograph that you need to tweak in Photoshop, but without adding transparency: export all your files from Photoshop as JPEG .jpg files and link to them. Why? Because
  • Linked Photoshop .psd files cause a big performance hit on large files. I have had files that were uneditable until I exported to JPEG .jpg format and linked to those.
  • JPEG .jpg files are compressed and lossy (some loss of detail) but in Photoshop you can tweak the compression vs. quality level, and the performance hit from InDesign having to expand them seems negligible. Some argue for TIFF .tif files which are not compressed, and seem like a reasonable alternative, but I've found the JPEG .jpg files work fine.
  • Pro Tip 1 (not mentioned anywhere in the Adobe documentation): there are ways to automate conversion of Photoshop .psd files to JPEG .jpg files. I use a Windows File Explorer replacement called Directory Opus, and in it, when looking at a folder full of Photoshop .psd files, I can select/highlight all of them, then right-click, and select "Convert to JPG" and in a few seconds I have all the exported JPEG .jpg files that I need. I have no idea what program provides this right-click functionality; if you can reproduce it in native Windows File Explorer, please post your success in this thread. If you can do it on a Mac, please also post your success in this thread.
  • Pro Tip 2 (not mentioned in the documentation): if you have a folder full of Photoshop .psd files as well as the JPEG .jpg files you exported, and your document has links to all of the Photoshop .psd files, you can relink all of the files from Photoshop .psd to JPEG .jpg files with a few clicks. In the InDesign Links Panel (icon of two chain links), select all of the Photoshop .psd files (you can also select all of the JPEG .jpg files as well, it doesn't matter) and then do not right-click (this is not in the right-click menu). Instead, from the hamburger menu (three small lines) at the top left of the InDesign Links Panel, select Relink File Extension… and then enter jpg and click Relink. That should relink all of your Photoshop .psd files with the corresponding JPEG .jpg files.
• Any size InDesign document, Photoshop .psd file with transparency:  follow the above instructions but, for a large document, convert to Portable Network Graphics .png format which, unlike JPEG .jpg format, supports transparency.
• Small InDesign document, Adobe Illustrator .ai files, with or without transparency: link to the .ai files so that you can, as above with Photoshop .psd files, right-click and "Edit Original."
• Large InDesign document, Adobe Illustrator .ai files, with or without transparency: export to Portable Network Graphics .png format as that deals better with large areas of the same color than JPEG .jpg files, and link to them as described above. While the performance hit is not as bad as with linking to Photoshop .psd files, it's significant.