Replace slice and comparison with endswith

src/PIL/ImImagePlugin.py

@@ -155,9 +155,9 @@ class ImImageFile(ImageFile.ImageFile):
                 msg = "not an IM file"
                 raise SyntaxError(msg)
 
-            if s[-2:] == b"\r\n":
+            if s.endswith(b"\r\n"):
                 s = s[:-2]
-            elif s[-1:] == b"\n":
+            elif s.endswith(b"\n"):
                 s = s[:-1]
 
             try:

src/PIL/MicImagePlugin.py

@@ -54,7 +54,7 @@ class MicImageFile(TiffImagePlugin.TiffImageFile):
         self.images = [
             path
             for path in self.ole.listdir()
-            if path[1:] and path[0][-4:] == ".ACI" and path[1] == "Image"
+            if path[1:] and path[0].endswith(".ACI") and path[1] == "Image"
         ]
 
         # if we didn't find any images, this is probably not

src/PIL/XpmImagePlugin.py

@@ -67,9 +67,9 @@ class XpmImageFile(ImageFile.ImageFile):
 
         for _ in range(pal):
             s = self.fp.readline()
-            if s[-2:] == b"\r\n":
+            if s.endswith(b"\r\n"):
                 s = s[:-2]
-            elif s[-1:] in b"\r\n":
+            elif s.endswith((b"\r", b"\n")):
                 s = s[:-1]
 
             c = s[1]