runner.go: Don't try to extract image tags for text models

When processing a prompt, we look for image tags of the form
[img-0], which are inserted by the Ollama server process.
However, this can cause errors if the original prompt has these
tags - typically an image not found error is returned.

This changes tag searching behavior to be similar to the 0.3.x
series, which will largely avoid these problems. However,they can
still happen when input text with these tags is used with image
models. The correct solution is to escape the tags but this is a
larger issue with special sequences in general so this is an
incremental fix that should avoid the problem for the majority
of cases.

llama/runner/runner.go

@@ -164,10 +164,16 @@ func (s *Server) NewSequence(prompt string, images []ImageData, params NewSequen
 // generating image embeddings for each image
 func (s *Server) inputs(prompt string, images []ImageData) ([]input, error) {
 	var inputs []input
+	var parts []string
+	var matches [][]string
 
-	re := regexp.MustCompile(`\[img-(\d+)\]`)
-	parts := re.Split(prompt, -1)
-	matches := re.FindAllStringSubmatch(prompt, -1)
+	if s.image != nil {
+		re := regexp.MustCompile(`\[img-(\d+)\]`)
+		parts = re.Split(prompt, -1)
+		matches = re.FindAllStringSubmatch(prompt, -1)
+	} else {
+		parts = []string{prompt}
+	}
 
 	for i, part := range parts {
 		// text - tokenize